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97374a1184
WHERE predicates containing references to empty tables in a subquery were handled incorrectly by the optimizer when executing EXPLAIN. As a result, the optimizer could try to evaluate such predicates rather than just stop with "Impossible WHERE noticed after reading const tables" as it would do in a non-subquery case. This led to valgrind errors and crashes. Fixed the code checking the above condition so that subqueries are not excluded and hence are handled in the same way as top level SELECTs. mysql-test/r/explain.result: Added a test case for bug #48419. mysql-test/r/ps.result: Updated test results to take the new (and more correct) "Extra" comments in execution plans. mysql-test/t/explain.test: Added a test case for bug #48419. sql/sql_select.cc: There is no point in excluding subqueries from checking for identically false WHERE conditions.
241 lines
11 KiB
Text
241 lines
11 KiB
Text
drop table if exists t1;
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create table t1 (id int not null, str char(10), unique(str));
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explain select * from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 0 const row not found
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insert into t1 values (1, null),(2, null),(3, "foo"),(4, "bar");
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select * from t1 where str is null;
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id str
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1 NULL
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2 NULL
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select * from t1 where str="foo";
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id str
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3 foo
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explain select * from t1 where str is null;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ref str str 11 const 1 Using where
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explain select * from t1 where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 ignore key (str) where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
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explain select * from t1 use key (str,str) where str="foo";
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 const str str 11 const 1
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explain select * from t1 use key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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explain select * from t1 ignore key (str,str,foo) where str="foo";
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ERROR 42000: Key 'foo' doesn't exist in table 't1'
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drop table t1;
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explain select 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used
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create table t1 (a int not null);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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insert into t1 values(1);
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explain select count(*) from t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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drop table t1;
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set names koi8r;
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create table <20><><EFBFBD> (<28><><EFBFBD>0 int, <20><><EFBFBD>1 int, key <20><><EFBFBD>0 (<28><><EFBFBD>0), key <20><><EFBFBD>01 (<28><><EFBFBD>0,<2C><><EFBFBD>1));
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (1);
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insert into <20><><EFBFBD> (<28><><EFBFBD>0) values (2);
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explain select <20><><EFBFBD>0 from <20><><EFBFBD> where <20><><EFBFBD>0=1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE <09><><EFBFBD> ref <09><><EFBFBD>0,<2C><><EFBFBD>01 <09><><EFBFBD>0 5 const 1 Using where; Using index
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drop table <20><><EFBFBD>;
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set names latin1;
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select 3 into @v1;
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explain select 3 into @v1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL No tables used
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create table t1(f1 int, f2 int);
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insert into t1 values (1,1);
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create view v1 as select * from t1 where f1=1;
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explain extended select * from v1 where f2=1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` where 1
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explain extended select * from t1 where 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where 0
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explain extended select * from t1 where 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` where 1
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explain extended select * from t1 having 0;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible HAVING
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Warnings:
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Note 1003 select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` having 0
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explain extended select * from t1 having 1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t1 system NULL NULL NULL NULL 1 100.00
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Warnings:
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Note 1003 select '1' AS `f1`,'1' AS `f2` from `test`.`t1` having 1
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drop view v1;
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drop table t1;
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CREATE TABLE t1(c INT);
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INSERT INTO t1 VALUES (),();
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CREATE TABLE t2 (b INT,
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b),
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KEY(b),KEY(b),KEY(b),KEY(b),KEY(b));
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INSERT INTO t2 VALUES (),(),();
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EXPLAIN SELECT 1 FROM
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(SELECT 1 FROM t2,t1 WHERE b < c GROUP BY 1 LIMIT 1) AS d2;
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id select_type table type possible_keys key key_len ref rows Extra
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X X X X X X X X X const row not found
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X X X X X X X X X
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X X X X X X X X X Range checked for each record (index map: 0xFFFFFFFFFF)
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DROP TABLE t2;
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DROP TABLE t1;
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CREATE TABLE t1(a INT);
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CREATE TABLE t2(a INT);
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INSERT INTO t1 VALUES (1),(2);
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INSERT INTO t2 VALUES (1),(2);
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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prepare s1 from
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'EXPLAIN EXTENDED SELECT 1
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FROM (SELECT COUNT(DISTINCT t1.a) FROM t1,t2 GROUP BY t1.a) AS s1';
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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execute s1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 100.00
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2 DERIVED t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort
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2 DERIVED t2 ALL NULL NULL NULL NULL 2 100.00 Using join buffer
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Warnings:
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Note 1003 select 1 AS `1` from (select count(distinct `test`.`t1`.`a`) AS `COUNT(DISTINCT t1.a)` from `test`.`t1` join `test`.`t2` group by `test`.`t1`.`a`) `s1`
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DROP TABLE t1,t2;
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CREATE TABLE t1 (a INT PRIMARY KEY);
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EXPLAIN EXTENDED SELECT COUNT(a) FROM t1 USE KEY(a);
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ERROR 42000: Key 'a' doesn't exist in table 't1'
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DROP TABLE t1;
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CREATE TABLE t1(a LONGTEXT);
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INSERT INTO t1 VALUES (repeat('a',@@global.max_allowed_packet));
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INSERT INTO t1 VALUES (repeat('b',@@global.max_allowed_packet));
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EXPLAIN SELECT DISTINCT 1 FROM t1,
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(SELECT DISTINCTROW a AS away FROM t1 GROUP BY a WITH ROLLUP) as d1
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WHERE t1.a = d1.a;
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ERROR 42S22: Unknown column 'd1.a' in 'where clause'
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DROP TABLE t1;
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#
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# Bug#48295:
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# explain extended crash with subquery and ONLY_FULL_GROUP_BY sql_mode
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#
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CREATE TABLE t1 (f1 INT);
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SELECT @@session.sql_mode INTO @old_sql_mode;
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SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
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EXPLAIN EXTENDED SELECT 1 FROM t1
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WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
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ERROR 42000: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
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SHOW WARNINGS;
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Level Code Message
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Error 1140 Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
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Note 1003 select 1 AS `1` from `test`.`t1` where <not>(<exists>(...))
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SET SESSION sql_mode=@old_sql_mode;
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DROP TABLE t1;
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End of 5.0 tests.
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#
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# Bug#37870: Usage of uninitialized value caused failed assertion.
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#
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create table t1 (dt datetime not null, t time not null);
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create table t2 (dt datetime not null);
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insert into t1 values ('2001-01-01 1:1:1', '1:1:1'),
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('2001-01-01 1:1:1', '1:1:1');
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insert into t2 values ('2001-01-01 1:1:1'), ('2001-01-01 1:1:1');
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY INNR ALL NULL NULL NULL NULL 2 Using where
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
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dt
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flush tables;
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EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY OUTR ALL NULL NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY INNR ALL NULL NULL NULL NULL 2 Using where
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flush tables;
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SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
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dt
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2001-01-01 01:01:01
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2001-01-01 01:01:01
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drop tables t1, t2;
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#
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# Bug#47669: Query showed by EXPLAIN EXTENDED gives different result from original query
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#
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CREATE TABLE t1 (c int);
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INSERT INTO t1 VALUES (NULL);
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CREATE TABLE t2 (d int);
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INSERT INTO t2 VALUES (NULL), (0);
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EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 system NULL NULL NULL NULL 1 100.00
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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Warnings:
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Note 1276 Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
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Note 1003 select (select 1 from `test`.`t2` where (`test`.`t2`.`d` = NULL)) AS `(SELECT 1 FROM t2 WHERE d = c)` from `test`.`t1`
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DROP TABLE t1, t2;
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#
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# Bug #48419: another explain crash..
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#
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (b BLOB, KEY b(b(100)));
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INSERT INTO t2 VALUES ('1'), ('2'), ('3');
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FLUSH TABLES;
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EXPLAIN SELECT 1 FROM t1 WHERE a = (SELECT 1 FROM t1 t JOIN t2 WHERE b <= 1 AND t.a);
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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 Impossible WHERE noticed after reading const tables
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2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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DROP TABLE t1, t2;
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End of 5.1 tests.
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