mirror of
https://github.com/MariaDB/server.git
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3877 lines
159 KiB
Text
3877 lines
159 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
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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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a1
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1 - 00
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1 - 01
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1 - 02
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/* E.5 opt_sum_query detects no matching min/max row or substitutes MIN/MAX with a const. */
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TODO this test produces wrong result due to missing logic to handle the case
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when JOIN::optimize detects an empty subquery result.
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explain
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select a1 from t1 where a1 in (select max(b1) from t2);
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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;
|