@@ -1307,7 +1307,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL PRIMARY 4 NULL 4 Using where; Using index
2 DEPENDENT SUBQUERY t1 unique_subquery PRIMARY PRIMARY 4 func 1 Using where
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY where (`test`.`t1`.`b` <> 30))))
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
a
2
...
...
@@ -1315,8 +1315,8 @@ a
explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL PRIMARY 4 NULL 4 Using where; Using index
2 DEPENDENT SUBQUERY t1 eq_ref PRIMARY PRIMARY 4 func 1 Using where
2 DEPENDENT SUBQUERY t3 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 Using where; Using index
2 DEPENDENT SUBQUERY t3 eq_ref PRIMARY PRIMARY 4 test.t1.b 1 Using index
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))
drop table t1, t2, t3;
...
...
@@ -1334,9 +1334,9 @@ a
explain extended select * from t2 where t2.a in (select a from t1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL a 5 NULL 4 Using where; Using index
2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 1001 Using index
2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 1001 Using index; Using where
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a)))
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
a
2
...
...
@@ -1346,7 +1346,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL a 5 NULL 4 Using where; Using index
2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 1001 Using index; Using where
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where (`test`.`t1`.`b` <> 30))))
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
a
2
...
...
@@ -1373,7 +1373,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 index NULL a 5 NULL 4 Using where; Using index
2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 1001 Using index; Using where
Warnings:
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where (`test`.`t1`.`b` <> 30))))
Note 1003 select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
drop table t1, t2, t3;
create table t1 (a int, b int);
create table t2 (a int, b int);
...
...
@@ -1737,7 +1737,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 12 Using where
2 DEPENDENT SUBQUERY t1 unique_subquery PRIMARY PRIMARY 4 func 1 Using index; Using where
Warnings:
Note 1003 select `test`.`t1`.`id` AS `id`,`test`.`t1`.`text` AS `text` from `test`.`t1` where (not(<in_optimizer>(`test`.`t1`.`id`,<exists>(<primary_index_lookup>(<cache>(`test`.`t1`.`id`) in t1 on PRIMARY where (`test`.`t1`.`id` < 8))))))
Note 1003 select `test`.`t1`.`id` AS `id`,`test`.`t1`.`text` AS `text` from `test`.`t1` where (not(<in_optimizer>(`test`.`t1`.`id`,<exists>(<primary_index_lookup>(<cache>(`test`.`t1`.`id`) in t1 on PRIMARY where ((`test`.`t1`.`id` < 8) and (<cache>(`test`.`t1`.`id`) = `test`.`t1`.`id`)))))))
explain extended select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY tt ALL NULL NULL NULL NULL 12 Using where
...
...
@@ -4303,4 +4303,35 @@ LEFT(t1.a1,1)
SELECT a2 FROM t2 WHERE t2.a2 IN (SELECT t1.a1 FROM t1,t3 WHERE t1.b1=t3.a3);
a2
DROP TABLE t1, t2, t3;
CREATE TABLE t1 (a CHAR(1), b VARCHAR(10));
INSERT INTO t1 VALUES ('a', 'aa');
INSERT INTO t1 VALUES ('a', 'aaa');
SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
a b
CREATE INDEX I1 ON t1 (a);
CREATE INDEX I2 ON t1 (b);
EXPLAIN SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY t1 index_subquery I1 I1 2 func 2 Using index; Using where
SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
a b
CREATE TABLE t2 (a VARCHAR(1), b VARCHAR(10));
INSERT INTO t2 SELECT * FROM t1;
CREATE INDEX I1 ON t2 (a);
CREATE INDEX I2 ON t2 (b);
EXPLAIN SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY t2 index_subquery I1 I1 4 func 2 Using index; Using where
SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
a b
EXPLAIN
SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
2 DEPENDENT SUBQUERY t1 index_subquery I1 I1 2 func 2 Using index; Using where
SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);