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cd34946657
Analysis: The failed assert is a result of calling Item_sum_distinct::clear() on an incomplete object for which Item_sum_distinct::setup() was not yet called. The reason is that JOIN::exec for the outer query calls JOIN::reinit() for all its subqueries, which in turn calls clear() for all aggregate functions of the subqueries. The call stack is: mysql_explain_union -> mysql_select -> JOIN::exec -> select_desribe -> mysql_explain_union -> mysql_select -> JOIN::reinit This assert doesn't fail in the main 5.3 because constant subqueries are being executed during the optimize phase of the outer query, thus the Unique object is created before calling JOIN::exec for the outer query, and Item_sum_distinct::clear() actually cleans the Unique object. Solution: The best solution is the obvious one - substitute the assert with a test whether Item_sum_distinct::tree is NULL.
3938 lines
162 KiB
Text
3938 lines
162 KiB
Text
drop table if exists t1, t2, t1_1024, t2_1024;
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drop procedure if exists make_t1_indexes;
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drop procedure if exists make_t2_indexes;
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drop procedure if exists remove_t1_indexes;
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drop procedure if exists remove_t2_indexes;
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drop procedure if exists add_materialization_data;
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drop procedure if exists delete_materialization_data;
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drop procedure if exists set_all_columns_not_null;
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drop procedure if exists set_all_columns_nullable;
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create table t1 (a1 char(8), a2 char(8), a3 char(8), a4 int);
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insert into t1 values ('1 - 00', '2 - 00', '3 - 00', 0);
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insert into t1 values ('1 - 01', '2 - 01', '3 - 01', 1);
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insert into t1 values ('1 - 02', '2 - 02', '3 - 02', 2);
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create table t2 (b1 char(8), b2 char(8), b3 char(8), b4 int);
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insert into t2 values ('1 - 01', '2 - 01', '3 - 01', 1);
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insert into t2 values ('1 - 01', '2 - 01', '3 - 02', 2);
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insert into t2 values ('1 - 02', '2 - 02', '3 - 03', 3);
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insert into t2 values ('1 - 02', '2 - 02', '3 - 04', 4);
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insert into t2 values ('1 - 03', '2 - 03', '3 - 05', 5);
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create table t1_1024 (a1 blob(1024), a2 blob(1024));
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insert into t1_1024 values (concat('1 - 00', repeat('x', 1018)), concat('2 - 00', repeat('x', 1018)));
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insert into t1_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
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create table t2_1024 (b1 blob(1024), b2 blob(1024));
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insert into t2_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
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insert into t2_1024 values (concat('1 - 02', repeat('x', 1018)), concat('2 - 02', repeat('x', 1018)));
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insert into t2_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
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insert into t2_1024 values (concat('1 - 04', repeat('x', 1018)), concat('2 - 04', repeat('x', 1018)));
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create procedure make_t1_indexes()
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begin
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create index it1i1 on t1 (a1);
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create index it1i2 on t1 (a2);
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create index it1i3 on t1 (a1, a2);
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create index it1_1024i1 on t1_1024 (a1(6));
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create index it1_1024i2 on t1_1024 (a2(6));
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create index it1_1024i3 on t1_1024 (a1(6), a2(6));
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end|
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create procedure make_t2_indexes()
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begin
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create index it2i1 on t2 (b1);
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create index it2i2 on t2 (b2);
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create index it2i3 on t2 (b1, b2);
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create unique index it2i4 on t2 (b1, b2, b3);
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create index it2_1024i1 on t2_1024 (b1(6));
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create index it2_1024i2 on t2_1024 (b2(6));
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create index it2_1024i3 on t2_1024 (b1(6), b2(6));
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end|
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create procedure remove_t1_indexes()
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begin
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drop index it1i1 on t1;
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drop index it1i2 on t1;
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drop index it1i3 on t1;
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drop index it1_1024i1 on t1_1024;
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drop index it1_1024i2 on t1_1024;
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drop index it1_1024i3 on t1_1024;
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end|
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create procedure remove_t2_indexes()
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begin
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drop index it2i1 on t2;
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drop index it2i2 on t2;
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drop index it2i3 on t2;
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drop index it2i4 on t2;
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drop index it2_1024i1 on t2_1024;
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drop index it2_1024i2 on t2_1024;
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drop index it2_1024i3 on t2_1024;
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end|
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create procedure add_materialization_data()
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begin
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insert into t1 values ('1 - 03', '2 - 03', '3 - 03', 3);
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insert into t1 values ('1 - 04', '2 - 04', '3 - 04', 4);
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insert into t1 values ('1 - 05', '2 - 05', '3 - 05', 5);
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insert into t1 values ('1 - 06', '2 - 06', '3 - 06', 6);
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insert into t1 values ('1 - 07', '2 - 07', '3 - 07', 7);
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insert into t1_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
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end|
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create procedure delete_materialization_data()
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begin
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delete from t1 where a1 >= '1 - 03';
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delete from t1_1024 where a1 >= '1 - 03';
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end|
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create procedure set_all_columns_not_null()
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begin
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alter table t1 modify a1 char(8) not null, modify a2 char(8) not null, modify a3 char(8) not null;
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alter table t2 modify b1 char(8) not null, modify b2 char(8) not null, modify b3 char(8) not null;
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end|
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create procedure set_all_columns_nullable()
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begin
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alter table t1 modify a1 char(8) null, modify a2 char(8) null, modify a3 char(8) null;
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alter table t2 modify b1 char(8) null, modify b2 char(8) null, modify b3 char(8) null;
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end|
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/******************************************************************************
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1. Both materialization and in-to-exists are ON, make a cost-based choice.
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******************************************************************************/
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set @@optimizer_switch='materialization=on,in_to_exists=on';
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/* 1.1 In-to-exists is cheaper */
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call make_t1_indexes();
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/* 1.1.1 non-indexed table access */
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/* A. Subqueries in the SELECT clause. */
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explain
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select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
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a1 a1 in (select b1 from t2 where b1 > '0')
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1 - 00 0
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1 - 01 1
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1 - 02 1
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explain
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select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
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a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
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1 - 00 2 - 00 0
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1 - 01 2 - 01 1
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1 - 02 2 - 02 1
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explain
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select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
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a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
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1 - 00 2 - 00 0
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1 - 01 2 - 01 1
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1 - 02 2 - 02 1
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/*
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B. "Natural" examples of subqueries without grouping that
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cannot be flattened into semijoin.
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*/
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explain
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select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
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a1
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1 - 00
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1 - 01
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1 - 02
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explain
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select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
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a1 a2
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1 - 00 2 - 00
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1 - 01 2 - 01
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1 - 02 2 - 02
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UNION subqueries are currently limited to only use IN-TO-EXISTS.
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explain
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select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i2 9 NULL 3 Using where; Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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3 DEPENDENT UNION t3 ALL NULL NULL NULL NULL 5 Using where
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NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
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select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
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a2
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2 - 01
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2 - 02
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explain
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select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ref it1i1,it1i3 it1i1 9 const 1 Using where; Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
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a1
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1 - 02
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explain
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select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using where; Using index
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
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a1 a2
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1 - 01 2 - 01
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1 - 02 2 - 02
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/* C. Subqueries in the WHERE clause with GROUP BY. */
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explain
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select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
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select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
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a1 a2 a3 a4
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1 - 01 2 - 01 3 - 01 1
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1 - 02 2 - 02 3 - 02 2
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explain
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select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
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select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
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a1 a2 a3 a4
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1 - 01 2 - 01 3 - 01 1
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1 - 02 2 - 02 3 - 02 2
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explain
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select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
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select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
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a1 a2 a3 a4
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1 - 01 2 - 01 3 - 01 1
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1 - 02 2 - 02 3 - 02 2
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explain
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select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
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select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
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a1 a2 a3 a4
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1 - 01 2 - 01 3 - 01 1
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explain
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select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
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select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
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a1 a2 a3 a4
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explain
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select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
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select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
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a1 a2 a3 a4
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1 - 01 2 - 01 3 - 01 1
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/*
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D. Subqueries for which materialization is not possible, and the
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optimizer reverts to in-to-exists.
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*/
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explain
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select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
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select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
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left(a1,7) left(a2,7)
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1 - 00x 2 - 00x
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1 - 01x 2 - 01x
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explain
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select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
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select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
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left(a1,7) left(a2,7)
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1 - 00x 2 - 00x
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1 - 01x 2 - 01x
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explain
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select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
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select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
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left(a1,7) left(a2,7)
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1 - 00x 2 - 00x
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1 - 01x 2 - 01x
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explain
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select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
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select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
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left(a1,7) left(a2,7)
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1 - 00x 2 - 00x
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1 - 01x 2 - 01x
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/* E. Edge cases. */
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/* E.1 Both materialization and in_to_exists cannot be off. */
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set @save_optimizer_switch=@@optimizer_switch;
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set @@optimizer_switch = 'materialization=off,in_to_exists=off';
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select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
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ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
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set @@optimizer_switch = @save_optimizer_switch;
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/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
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explain
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select '1 - 03' in (select b1 from t2 where b1 > '0');
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
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select '1 - 03' in (select b1 from t2 where b1 > '0');
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'1 - 03' in (select b1 from t2 where b1 > '0')
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1
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/* E.3 Subqueries without tables. */
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explain
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select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 18 NULL 3 Using where; Using index
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Warnings:
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Note 1249 Select 2 was reduced during optimization
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select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
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a1
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1 - 00
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1 - 01
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1 - 02
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UNION subqueries are currently limited to only use IN-TO-EXISTS.
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explain
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select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
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2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
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3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
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NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
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select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
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a1
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1 - 02
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/* E.4 optimize_cond detects FALSE where/having clause. */
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explain
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select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
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2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 1.1.2 indexed table access, nullabale columns. */
|
|
call make_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i3 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i3 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i2 it2i2 9 func 2 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 18 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i2 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 27 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ref it1i1,it1i3 it1i1 9 const 1 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 18 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 1 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 27 NULL 1 Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 27 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 27 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 const 2 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 18 NULL 3 Using where; Using index
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 1.1.3 indexed table access, non-nullabale columns. */
|
|
call set_all_columns_not_null();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i4 8 func 1 Using index; Using where
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i4,it2i1,it2i2,it2i3 it2i4 8 func 2 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i4,it2i1,it2i2,it2i3 it2i4 8 func 2 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i2 it2i2 8 func 2 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 16 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i2 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 24 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ref it1i1,it1i3 it1i1 8 const 1 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 16 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 1 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 24 NULL 1 Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 24 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 24 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 8 const 5 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 16 NULL 3 Using where; Using index
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
call set_all_columns_nullable();
|
|
|
|
/* 1.2 Materialization is cheaper */
|
|
call add_materialization_data();
|
|
call remove_t1_indexes();
|
|
/* 1.2.1 non-indexed table access */
|
|
call remove_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
3 DEPENDENT UNION t3 ALL NULL NULL NULL NULL 5 Using where
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 1.2.2 indexed table access, nullabale columns. */
|
|
call make_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 5 Using where; Using index
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i2,it2i3 it2i3 9 NULL 4 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i2 it2i2 9 NULL 5 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 27 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ref it2i2 it2i2 9 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i4 27 NULL 5 Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 5 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 27 NULL 6 Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 27 NULL 6 Using where; Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 27 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 const 2 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 1.2.3 indexed table access, non-nullabale columns. */
|
|
call set_all_columns_not_null();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 5 Using where; Using index
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i2,it2i3 it2i3 8 NULL 4 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i2 it2i2 8 NULL 5 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 24 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 ref it2i2 it2i2 8 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i2,it2i3 it2i4 24 NULL 5 Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 5 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 24 NULL 6 Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 24 NULL 6 Using where; Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 24 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 8 const 5 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
call set_all_columns_nullable();
|
|
/******************************************************************************
|
|
2. Materialization is OFF, in-to-exists is ON, materialization is cheaper.
|
|
******************************************************************************/
|
|
set @@optimizer_switch='materialization=off,in_to_exists=on';
|
|
/* 2.1 non-indexed table access */
|
|
call remove_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
3 DEPENDENT UNION t3 ALL NULL NULL NULL NULL 5 Using where
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 2.2 indexed table access, nullabale columns. */
|
|
call make_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i3 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i3 9 func 2 Using index; Using where; Full scan on NULL key
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i2 it2i2 9 func 2 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 18 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 27 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 18 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 1 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 27 NULL 1 Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 27 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 27 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 const 2 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 2.3 indexed table access, non-nullabale columns. */
|
|
call set_all_columns_not_null();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i4 8 func 1 Using index; Using where
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
1 - 03 1
|
|
1 - 04 0
|
|
1 - 05 0
|
|
1 - 06 0
|
|
1 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 ref it2i4,it2i1,it2i2,it2i3 it2i4 8 func 2 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8
|
|
2 DEPENDENT SUBQUERY t2 ref it2i4,it2i1,it2i2,it2i3 it2i4 8 func 2 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
1 - 03 2 - 03 1
|
|
1 - 04 2 - 04 0
|
|
1 - 05 2 - 05 0
|
|
1 - 06 2 - 06 0
|
|
1 - 07 2 - 07 0
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i2 it2i2 8 func 2 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 16 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
1 - 04 2 - 04
|
|
1 - 05 2 - 05
|
|
1 - 06 2 - 06
|
|
1 - 07 2 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 24 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
2 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i2,it2i3 it2i4 16 func,func 1 Using index; Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
1 - 03 2 - 03
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 1 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
1 - 03 2 - 03 3 - 03 3
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 24 NULL 1 Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 index NULL it2i4 24 NULL 1 Using where; Using index
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 24 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL NULL NULL NULL NULL 3 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
1 - 03x 2 - 03x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 8 const 5 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
1 - 03
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
1 - 03
|
|
1 - 04
|
|
1 - 05
|
|
1 - 06
|
|
1 - 07
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
1 - 03
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 8 Using where
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
call set_all_columns_nullable();
|
|
/******************************************************************************
|
|
3. Materialization is ON, in-to-exists is OFF, in-to-exists is cheaper.
|
|
******************************************************************************/
|
|
set @@optimizer_switch='materialization=on,in_to_exists=off';
|
|
call delete_materialization_data();
|
|
call make_t1_indexes();
|
|
/* 3.1 non-indexed table access */
|
|
call remove_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i2 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
3 DEPENDENT UNION t3 ALL NULL NULL NULL NULL 5 Using where
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ref it1i1,it1i3 it1i1 9 const 1 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where; Using temporary; Using filesort
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 ALL NULL NULL NULL NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 18 NULL 3 Using where; Using index
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 5 Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 3.2 indexed table access, nullabale columns. */
|
|
call make_t2_indexes();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 5 Using where; Using index
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using index
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i3 9 NULL 4 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index NULL it2i2 9 NULL 5 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i2 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 9 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 27 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ref it1i1,it1i3 it1i1 9 const 1 Using where; Using index
|
|
2 SUBQUERY t2 ref it2i2 it2i2 9 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index NULL it2i4 27 NULL 5 Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 9 NULL 5 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 18 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 27 NULL 6 Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 27 NULL 6 Using where; Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 27 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 9 const 2 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 18 NULL 3 Using where; Using index
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 18 NULL 3 Using where; Using index
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 9 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
/* 3.3 indexed table access, non-nullabale columns. */
|
|
call set_all_columns_not_null();
|
|
|
|
/* A. Subqueries in the SELECT clause. */
|
|
explain
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 5 Using where; Using index
|
|
select a1, a1 in (select b1 from t2 where b1 > '0') from t1;
|
|
a1 a1 in (select b1 from t2 where b1 > '0')
|
|
1 - 00 0
|
|
1 - 01 1
|
|
1 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
explain
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using index
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i3 8 NULL 4 Using where; Using index
|
|
select a1, a2, (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9') from t1;
|
|
a1 a2 (a1, a2) in (select b1, b2 from t2 where b1 > '0' and b1 < '9')
|
|
1 - 00 2 - 00 0
|
|
1 - 01 2 - 01 1
|
|
1 - 02 2 - 02 1
|
|
|
|
/*
|
|
B. "Natural" examples of subqueries without grouping that
|
|
cannot be flattened into semijoin.
|
|
*/
|
|
explain
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index NULL it2i2 8 NULL 5 Using index
|
|
select a1 from t1 where a1 in (select b2 from t2) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0') or a2 < '9';
|
|
a1 a2
|
|
1 - 00 2 - 00
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i2 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY t2 ref it2i2 it2i2 8 func 2 Using index
|
|
3 DEPENDENT UNION t3 index NULL it2i4 24 NULL 5 Using where; Using index
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a2 from t1 where a2 in (select b2 from t2 UNION select b3 from t2 as t3);
|
|
a2
|
|
2 - 01
|
|
2 - 02
|
|
|
|
explain
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ref it1i1,it1i3 it1i1 8 const 1 Using where; Using index
|
|
2 SUBQUERY t2 ref it2i2 it2i2 8 const 1 Using index condition
|
|
select a1 from t1 where a1 = '1 - 02' and a1 in (select max(b1) from t2 where b2 = '2 - 02');
|
|
a1
|
|
1 - 02
|
|
|
|
explain
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i3 16 NULL 3 Using where; Using index
|
|
2 SUBQUERY t2 index NULL it2i4 24 NULL 5 Using index
|
|
select a1, a2 from t1 where (a1, a2) in (select b1, b2 from t2 order by b3);
|
|
a1 a2
|
|
1 - 01 2 - 01
|
|
1 - 02 2 - 02
|
|
|
|
/* C. Subqueries in the WHERE clause with GROUP BY. */
|
|
explain
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i1 8 NULL 5 Using where; Using index
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 index it2i4,it2i1,it2i3 it2i3 16 NULL 5 Using where; Using index
|
|
select * from t1 where (a1, a2) in (select b1, b2 from t2 where b1 > '0' group by b1, b2 having b2 < '2 - 04');
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
1 - 02 2 - 02 3 - 02 2
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 24 NULL 6 Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 group by b1, b2, b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
explain
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range NULL it2i4 24 NULL 6 Using where; Using index for group-by
|
|
select * from t1 where (a1, a2, a3) in (select b1, b2, b3 from t2 where b3 = '3 - 02' group by b1, b2);
|
|
a1 a2 a3 a4
|
|
|
|
explain
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
|
|
2 SUBQUERY t2 range it2i4,it2i1,it2i3 it2i4 24 NULL 2 Using where; Using index for group-by
|
|
select * from t1 where (a1,a2,a3) in (select b1,b2,b3 from t2 where b1 = '1 - 01' group by b1,b2,b3);
|
|
a1 a2 a3 a4
|
|
1 - 01 2 - 01 3 - 01 1
|
|
|
|
/*
|
|
D. Subqueries for which materialization is not possible, and the
|
|
optimizer reverts to in-to-exists.
|
|
*/
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i3 it2_1024i3 9 func 1 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select b1 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 index_subquery it2_1024i1,it2_1024i2,it2_1024i3 it2_1024i1 9 func 2 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select b1, b2 from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
explain
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1_1024 ALL it1_1024i2 NULL NULL NULL 2 Using where
|
|
2 DEPENDENT SUBQUERY t2_1024 range it2_1024i1,it2_1024i3 it2_1024i1 9 NULL 4 Using where
|
|
select left(a1,7), left(a2,7) from t1_1024 where (a1,a2) in (select substring(b1,1,1024), substring(b2,1,1024) from t2_1024 where b1 > '0') or a2 < '9';
|
|
left(a1,7) left(a2,7)
|
|
1 - 00x 2 - 00x
|
|
1 - 01x 2 - 01x
|
|
|
|
|
|
/* E. Edge cases. */
|
|
|
|
/* E.1 Both materialization and in_to_exists cannot be off. */
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch = 'materialization=off,in_to_exists=off';
|
|
select * from t1 where a1 in (select b1 from t2 where b1 > '0' group by b1);
|
|
ERROR HY000: At least one of the 'in_to_exists' or 'materialization' optimizer_switch flags must be 'on'.
|
|
set @@optimizer_switch = @save_optimizer_switch;
|
|
/* E.2 Outer query without tables, always uses IN-TO-EXISTS. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY t2 index_subquery it2i4,it2i1,it2i3 it2i1 8 const 5 Using index; Using where
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0')
|
|
1
|
|
/* E.3 Subqueries without tables. */
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i1,it1i2,it1i3 it1i3 16 NULL 3 Using where; Using index
|
|
Warnings:
|
|
Note 1249 Select 2 was reduced during optimization
|
|
select a1 from t1 where a1 in (select '1 - 03') or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
UNION subqueries are currently limited to only use IN-TO-EXISTS.
|
|
explain
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
select a1 from t1 where a1 in (select '1 - 03' UNION select '1 - 02');
|
|
a1
|
|
1 - 02
|
|
/* E.4 optimize_cond detects FALSE where/having clause. */
|
|
explain
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index it1i2 it1i3 16 NULL 3 Using where; Using index
|
|
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
|
|
select a1 from t1 where a1 in (select b1 from t2 where b1 = b2 and b2 = '1 - 03' and b1 = '1 - 02' ) or a2 < '9';
|
|
a1
|
|
1 - 00
|
|
1 - 01
|
|
1 - 02
|
|
/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
|
|
TODO this test produces wrong result due to missing logic to handle the case
|
|
when JOIN::optimize detects an empty subquery result.
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
|
|
select a1 from t1 where a1 in (select max(b1) from t2);
|
|
a1
|
|
|
|
explain
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY t1 index NULL it1i1 8 NULL 3 Using where; Using index
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No matching min/max row
|
|
select a1 from t1 where a1 in (select max(b1) from t2 where b1 = '7 - 02');
|
|
a1
|
|
/* E.6 make_join_select detects impossible WHERE. *
|
|
TODO
|
|
/* E.7 constant optimization detects "no matching row in const table". */
|
|
TODO
|
|
/* E.8 Impossible WHERE noticed after reading const tables. */
|
|
explain
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL No tables used
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
select '1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0');
|
|
'1 - 03' in (select b1 from t2 where b1 > '0' and b1 < '0')
|
|
0
|
|
|
|
/* F. UPDATE/DELETE with subqueries. */
|
|
|
|
TODO
|
|
|
|
call set_all_columns_nullable();
|
|
drop procedure make_t1_indexes;
|
|
drop procedure make_t2_indexes;
|
|
drop procedure remove_t1_indexes;
|
|
drop procedure remove_t2_indexes;
|
|
drop procedure add_materialization_data;
|
|
drop procedure delete_materialization_data;
|
|
drop procedure set_all_columns_not_null;
|
|
drop procedure set_all_columns_nullable;
|
|
drop table t1, t2, t1_1024, t2_1024;
|
|
#
|
|
# LP BUG#643424 valgrind warning in choose_subquery_plan()
|
|
#
|
|
CREATE TABLE t1 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
c2 int(11) DEFAULT NULL,
|
|
PRIMARY KEY (pk),
|
|
KEY c2 (c2));
|
|
INSERT INTO t1 VALUES (1,NULL,2);
|
|
INSERT INTO t1 VALUES (2,7,9);
|
|
INSERT INTO t1 VALUES (9,NULL,8);
|
|
CREATE TABLE t2 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
c2 int(11) DEFAULT NULL,
|
|
PRIMARY KEY (pk),
|
|
KEY c2 (c2));
|
|
INSERT INTO t2 VALUES (1,1,7);
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
|
|
SELECT pk FROM t1 WHERE (c2, c1) IN (SELECT c2, c2 FROM t2);
|
|
pk
|
|
set session optimizer_switch=@save_optimizer_switch;
|
|
drop table t1, t2;
|
|
#
|
|
# LP BUG#652727 Crash in create_ref_for_key()
|
|
#
|
|
CREATE TABLE t2 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
PRIMARY KEY (pk));
|
|
INSERT INTO t2 VALUES (10,7);
|
|
INSERT INTO t2 VALUES (11,1);
|
|
INSERT INTO t2 VALUES (17,NULL);
|
|
CREATE TABLE t1 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
PRIMARY KEY (pk));
|
|
INSERT INTO t1 VALUES (15,1);
|
|
INSERT INTO t1 VALUES (19,NULL);
|
|
CREATE TABLE t3 (c2 int(11) DEFAULT NULL, KEY c2 (c2));
|
|
INSERT INTO t3 VALUES (1);
|
|
set @save_optimizer_switch=@@optimizer_switch;
|
|
set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
|
|
SELECT c2
|
|
FROM t3
|
|
WHERE (2, 6) IN (SELECT t1.c1, t1.c1 FROM t1 STRAIGHT_JOIN t2 ON t2.pk = t1.pk);
|
|
c2
|
|
set session optimizer_switch=@save_optimizer_switch;
|
|
drop table t1, t2, t3;
|
|
#
|
|
# LP BUG#641245 Crash in Item_equal::contains
|
|
#
|
|
CREATE TABLE t1 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
c2 int(11) DEFAULT NULL,
|
|
c3 varchar(1) DEFAULT NULL,
|
|
c4 varchar(1) DEFAULT NULL,
|
|
PRIMARY KEY (pk),
|
|
KEY c2 (c2),
|
|
KEY c3 (c3,c2));
|
|
INSERT INTO t1 VALUES (10,7,8,'v','v');
|
|
INSERT INTO t1 VALUES (11,1,9,'r','r');
|
|
INSERT INTO t1 VALUES (12,5,9,'a','a');
|
|
create table t1a like t1;
|
|
insert into t1a select * from t1;
|
|
create table t1b like t1;
|
|
insert into t1b select * from t1;
|
|
CREATE TABLE t2 (
|
|
pk int(11) NOT NULL AUTO_INCREMENT,
|
|
c1 int(11) DEFAULT NULL,
|
|
c2 int(11) DEFAULT NULL,
|
|
c3 varchar(1) DEFAULT NULL,
|
|
c4 varchar(1) DEFAULT NULL,
|
|
PRIMARY KEY (pk),
|
|
KEY c2 (c2),
|
|
KEY c3 (c3,c2));
|
|
INSERT INTO t2 VALUES (1,NULL,2,'w','w');
|
|
INSERT INTO t2 VALUES (2,7,9,'m','m');
|
|
set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
|
|
EXPLAIN EXTENDED SELECT pk
|
|
FROM t1
|
|
WHERE c1 IN
|
|
(SELECT t1a.c1
|
|
FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
|
|
t1a ON (t1a.c2 = t1b.pk AND 2)
|
|
WHERE t1.pk) ;
|
|
id select_type table type possible_keys key key_len ref rows filtered Extra
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 100.00 Using where
|
|
2 DEPENDENT SUBQUERY t2 index c3 c3 9 NULL 2 100.00 Using index
|
|
2 DEPENDENT SUBQUERY t1b ALL NULL NULL NULL NULL 3 100.00 Using where; Using join buffer
|
|
2 DEPENDENT SUBQUERY t1a ref c2 c2 5 test.t1b.pk 2 100.00 Using where
|
|
Warnings:
|
|
Note 1276 Field or reference 'test.t1.pk' of SELECT #2 was resolved in SELECT #1
|
|
Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,(`test`.`t1`.`pk` and (`test`.`t1b`.`c4` = `test`.`t2`.`c3`) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`))>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where (`test`.`t1`.`pk` and (`test`.`t1b`.`c4` = `test`.`t2`.`c3`) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`)))))
|
|
SELECT pk
|
|
FROM t1
|
|
WHERE c1 IN
|
|
(SELECT t1a.c1
|
|
FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
|
|
t1a ON (t1a.c2 = t1b.pk AND 2)
|
|
WHERE t1.pk) ;
|
|
pk
|
|
DROP TABLE t1, t1a, t1b, t2;
|
|
#
|
|
# LP BUG#714808 Assertion `outer_lookup_keys <= outer_record_count'
|
|
# failed with materialization
|
|
CREATE TABLE t1 ( pk int(11), PRIMARY KEY (pk)) ;
|
|
CREATE TABLE t2 ( f2 int(11)) ;
|
|
CREATE TABLE t3 ( f1 int(11), f3 varchar(1), KEY (f1)) ;
|
|
INSERT INTO t3 VALUES (7,'f');
|
|
set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
|
|
EXPLAIN
|
|
SELECT t1.*
|
|
FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
|
|
WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
SELECT t1.*
|
|
FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
|
|
WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
|
|
pk
|
|
drop table t1,t2,t3;
|
|
#
|
|
# LP BUG#714999 Second crash in select_describe() with nested subqueries
|
|
#
|
|
CREATE TABLE t1 ( pk int(11)) ;
|
|
INSERT INTO t1 VALUES (29);
|
|
CREATE TABLE t2 ( f1 varchar(1)) ;
|
|
INSERT INTO t2 VALUES ('f'),('d');
|
|
CREATE TABLE t3 ( f2 varchar(1)) ;
|
|
EXPLAIN SELECT f2 FROM t3 WHERE (
|
|
SELECT MAX( pk ) FROM t1
|
|
WHERE EXISTS (
|
|
SELECT DISTINCT f1
|
|
FROM t2
|
|
)
|
|
) IS NULL ;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
2 SUBQUERY t1 system NULL NULL NULL NULL 1
|
|
3 SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using temporary
|
|
drop table t1, t2;
|
|
#
|
|
# LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
|
|
#
|
|
CREATE TABLE t2 ( f2 int(11)) ;
|
|
CREATE TABLE t1 ( f3 int(11), KEY (f3)) ;
|
|
INSERT INTO t1 VALUES (6),(4);
|
|
EXPLAIN
|
|
SELECT * FROM (SELECT * FROM t2) AS a2
|
|
WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
|
|
3 SUBQUERY t1 index NULL f3 5 NULL 2 Using index
|
|
2 DERIVED NULL NULL NULL NULL NULL NULL NULL no matching row in const table
|
|
insert into t2 values (1),(2);
|
|
EXPLAIN
|
|
SELECT * FROM (SELECT * FROM t2) AS a2
|
|
WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
|
|
3 SUBQUERY t1 index NULL f3 5 NULL 2 Using index
|
|
2 DERIVED t2 ALL NULL NULL NULL NULL 2
|