drop table if exists t0, t1, t2, t3, t4, t5; create table t1 (oref int, grp int, ie int) ; insert into t1 (oref, grp, ie) values (1, 1, 1), (1, 1, 1), (1, 2, NULL), (2, 1, 3), (3, 1, 4), (3, 2, NULL); create table t2 (oref int, a int); insert into t2 values (1, 1), (2, 2), (3, 3), (4, NULL), (2, NULL); select a, oref, a in (select max(ie) from t1 where oref=t2.oref group by grp) Z from t2; a oref Z 1 1 1 2 2 0 3 3 NULL NULL 4 0 NULL 2 NULL explain extended select a, oref, a in (select max(ie) from t1 where oref=t2.oref group by grp) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 100.00 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 6 100.00 Using where; Using temporary; Using filesort Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) AS `max(ie)` from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`)))))) AS `Z` from `test`.`t2` explain extended select a, oref from t2 where a in (select max(ie) from t1 where oref=t2.oref group by grp); id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 100.00 Using where 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 6 100.00 Using where; Using temporary; Using filesort Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(select max(`test`.`t1`.`ie`) AS `max(ie)` from `test`.`t1` where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) group by `test`.`t1`.`grp` having (<cache>(`test`.`t2`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`))))) select a, oref, a in ( select max(ie) from t1 where oref=t2.oref group by grp union select max(ie) from t1 where oref=t2.oref group by grp ) Z from t2; a oref Z 1 1 1 2 2 0 3 3 NULL NULL 4 0 NULL 2 NULL create table t3 (a int); insert into t3 values (NULL), (NULL); flush status; select a in (select max(ie) from t1 where oref=4 group by grp) from t3; a in (select max(ie) from t1 where oref=4 group by grp) 0 0 show status like 'Handler_read_rnd_next'; Variable_name Value Handler_read_rnd_next 11 select ' ^ This must show 11' Z; Z ^ This must show 11 explain extended select a in (select max(ie) from t1 where oref=4 group by grp) from t3; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t3 ALL NULL NULL NULL NULL 2 100.00 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 6 100.00 Using where; Using temporary; Using filesort Warnings: Note 1003 select <in_optimizer>(`test`.`t3`.`a`,<exists>(select max(`test`.`t1`.`ie`) AS `max(ie)` from `test`.`t1` where (`test`.`t1`.`oref` = 4) group by `test`.`t1`.`grp` having trigcond((<cache>(`test`.`t3`.`a`) = <ref_null_helper>(max(`test`.`t1`.`ie`)))))) AS `a in (select max(ie) from t1 where oref=4 group by grp)` from `test`.`t3` drop table t1, t2, t3; create table t1 (a int, oref int, key(a)); insert into t1 values (1, 1), (1, NULL), (2, 3), (2, NULL), (3, NULL); create table t2 (a int, oref int); insert into t2 values (1, 1), (2,2), (NULL, 3), (NULL, 4); select oref, a, a in (select a from t1 where oref=t2.oref) Z from t2; oref a Z 1 1 1 2 2 0 3 NULL NULL 4 NULL 0 explain extended select oref, a, a in (select a from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 4 100.00 2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 2 100.00 Using where; Full scan on NULL key Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,<in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a checking NULL where (`test`.`t1`.`oref` = `test`.`t2`.`oref`) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t2` flush status; select oref, a from t2 where a in (select a from t1 where oref=t2.oref); oref a 1 1 show status like '%Handler_read_rnd_next'; Variable_name Value Handler_read_rnd_next 5 delete from t2; insert into t2 values (NULL, 0),(NULL, 0), (NULL, 0), (NULL, 0); flush status; select oref, a, a in (select a from t1 where oref=t2.oref) Z from t2; oref a Z 0 NULL 0 0 NULL 0 0 NULL 0 0 NULL 0 show status like '%Handler_read%'; Variable_name Value Handler_read_first 0 Handler_read_key 0 Handler_read_next 0 Handler_read_prev 0 Handler_read_rnd 0 Handler_read_rnd_next 29 select 'No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1.' Z; Z No key lookups, seq reads: 29= 5 reads from t2 + 4 * 6 reads from t1. drop table t1, t2; create table t1 (a int, b int, primary key (a)); insert into t1 values (1,1), (3,1),(100,1); create table t2 (a int, b int); insert into t2 values (1,1),(2,1),(NULL,1),(NULL,0); select a,b, a in (select a from t1 where t1.b = t2.b) Z from t2 ; a b Z 1 1 1 2 1 0 NULL 1 NULL NULL 0 0 drop table t1, t2; create table t1 (a int, b int, key(a)); insert into t1 values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9); create table t2 like t1; insert into t2 select * from t1; update t2 set b=1; create table t3 (a int, oref int); insert into t3 values (1, 1), (NULL,1), (NULL,0); select a, oref, t3.a in (select t1.a from t1, t2 where t1.b=t2.a and t2.b=t3.oref) Z from t3; a oref Z 1 1 1 NULL 1 NULL NULL 0 0 explain extended select a, oref, t3.a in (select t1.a from t1, t2 where t1.b=t2.a and t2.b=t3.oref) Z from t3; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t3 ALL NULL NULL NULL NULL 3 100.00 2 DEPENDENT SUBQUERY t1 ref_or_null a a 5 func 4 100.00 Using where; Full scan on NULL key 2 DEPENDENT SUBQUERY t2 ref a a 5 test.t1.b 1 100.00 Using where Warnings: Note 1276 Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`)))) AS `Z` from `test`.`t3` drop table t1, t2, t3; create table t1 (a int NOT NULL, b int NOT NULL, key(a)); insert into t1 values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9); create table t2 like t1; insert into t2 select * from t1; update t2 set b=1; create table t3 (a int, oref int); insert into t3 values (1, 1), (NULL,1), (NULL,0); select a, oref, t3.a in (select t1.a from t1, t2 where t1.b=t2.a and t2.b=t3.oref) Z from t3; a oref Z 1 1 1 NULL 1 NULL NULL 0 0 This must show a trig_cond: explain extended select a, oref, t3.a in (select t1.a from t1, t2 where t1.b=t2.a and t2.b=t3.oref) Z from t3; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t3 ALL NULL NULL NULL NULL 3 100.00 2 DEPENDENT SUBQUERY t1 ref a a 4 func 2 100.00 Using where; Full scan on NULL key 2 DEPENDENT SUBQUERY t2 ref a a 4 test.t1.b 1 100.00 Using where Warnings: Note 1276 Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`))))) AS `Z` from `test`.`t3` drop table t1,t2,t3; create table t1 (oref int, grp int); insert into t1 (oref, grp) values (1, 1), (1, 1); create table t2 (oref int, a int); insert into t2 values (1, NULL), (2, NULL); select a, oref, a in (select count(*) from t1 group by grp having grp=t2.oref) Z from t2; a oref Z NULL 1 NULL NULL 2 0 This must show a trig_cond: explain extended select a, oref, a in (select count(*) from t1 group by grp having grp=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 2 100.00 Using temporary; Using filesort Warnings: Note 1276 Field or reference 't2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`a` AS `a`,`test`.`t2`.`oref` AS `oref`,<in_optimizer>(`test`.`t2`.`a`,<exists>(select count(0) AS `count(*)` from `test`.`t1` group by `test`.`t1`.`grp` having ((`test`.`t1`.`grp` = `test`.`t2`.`oref`) and trigcond((<cache>(`test`.`t2`.`a`) = <ref_null_helper>(count(0))))))) AS `Z` from `test`.`t2` drop table t1, t2; create table t1 (a int, b int, primary key (a)); insert into t1 values (1,1), (3,1),(100,1); create table t2 (a int, b int); insert into t2 values (1,1),(2,1),(NULL,1),(NULL,0); select a,b, a in (select a from t1 where t1.b = t2.b union select a from t1 where t1.b = t2.b) Z from t2 ; a b Z 1 1 1 2 1 0 NULL 1 NULL NULL 0 0 select a,b, a in (select a from t1 where t1.b = t2.b) Z from t2 ; a b Z 1 1 1 2 1 0 NULL 1 NULL NULL 0 0 drop table t1, t2; create table t3 (a int); insert into t3 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t2 (a int, b int, oref int); insert into t2 values (NULL,1, 100), (NULL,2, 100); create table t1 (a int, b int, c int, key(a,b)); insert into t1 select 2*A, 2*A, 100 from t3; explain extended select a,b, oref, (a,b) in (select a,b from t1 where c=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 2 DEPENDENT SUBQUERY t1 index_subquery a a 5 func 2 100.00 Using where; Full scan on NULL key Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`oref` AS `oref`,<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a checking NULL where ((`test`.`t1`.`c` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`b`) or isnull(`test`.`t1`.`b`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`a`)) and trigcond(<is_not_null_test>(`test`.`t1`.`b`)))))) AS `Z` from `test`.`t2` select a,b, oref, (a,b) in (select a,b from t1 where c=t2.oref) Z from t2; a b oref Z NULL 1 100 0 NULL 2 100 NULL create table t4 (x int); insert into t4 select A.a + 10*B.a from t1 A, t1 B; explain extended select a,b, oref, (a,b) in (select a,b from t1,t4 where c=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 2 100.00 2 DEPENDENT SUBQUERY t1 ref_or_null a a 5 func 2 100.00 Using where; Full scan on NULL key 2 DEPENDENT SUBQUERY t4 ALL NULL NULL NULL NULL 100 100.00 Using where; Using join buffer Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,`test`.`t2`.`oref` AS `oref`,<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t4` where ((`test`.`t1`.`c` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`b`) or isnull(`test`.`t1`.`b`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`a`)) and trigcond(<is_not_null_test>(`test`.`t1`.`b`))))) AS `Z` from `test`.`t2` select a,b, oref, (a,b) in (select a,b from t1,t4 where c=t2.oref) Z from t2; a b oref Z NULL 1 100 0 NULL 2 100 NULL drop table t1,t2,t3,t4; create table t1 (oref char(4), grp int, ie1 int, ie2 int); insert into t1 (oref, grp, ie1, ie2) values ('aa', 10, 2, 1), ('aa', 10, 1, 1), ('aa', 20, 2, 1), ('bb', 10, 3, 1), ('cc', 10, 4, 2), ('cc', 20, 3, 2), ('ee', 10, 2, 1), ('ee', 10, 1, 2), ('ff', 20, 2, 2), ('ff', 20, 1, 2); create table t2 (oref char(4), a int, b int); insert into t2 values ('ee', NULL, 1), ('bb', 2, 1), ('ff', 2, 2), ('cc', 3, NULL), ('bb', NULL, NULL), ('aa', 1, 1), ('dd', 1, NULL); alter table t1 add index idx(ie1,ie2); select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2 where a=3 and b is null ; oref a b Z cc 3 NULL NULL insert into t2 values ('new1', 10,10); insert into t1 values ('new1', 1234, 10, NULL); select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2 where a=10 and b=10; oref a b Z new1 10 10 NULL explain extended select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2 where a=10 and b=10; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 8 100.00 Using where 2 DEPENDENT SUBQUERY t1 index_subquery idx idx 5 func 4 100.00 Using where; Full scan on NULL key Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`)))))) AS `Z` from `test`.`t2` where ((`test`.`t2`.`b` = 10) and (`test`.`t2`.`a` = 10)) drop table t1, t2; create table t1 (oref char(4), grp int, ie int); insert into t1 (oref, grp, ie) values ('aa', 10, 2), ('aa', 10, 1), ('aa', 20, NULL), ('bb', 10, 3), ('cc', 10, 4), ('cc', 20, NULL), ('ee', 10, NULL), ('ee', 10, NULL), ('ff', 20, 2), ('ff', 20, 1); create table t2 (oref char(4), a int); insert into t2 values ('ee', NULL), ('bb', 2), ('ff', 2), ('cc', 3), ('aa', 1), ('dd', NULL), ('bb', NULL); select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; oref a Z ee NULL NULL bb 2 0 ff 2 1 cc 3 NULL aa 1 1 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select ie from t1 where oref=t2.oref); oref a ff 2 aa 1 select oref, a from t2 where a not in (select ie from t1 where oref=t2.oref); oref a bb 2 dd NULL select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2; oref a Z ee NULL NULL bb 2 0 ff 2 0 cc 3 NULL aa 1 1 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select min(ie) from t1 where oref=t2.oref group by grp); oref a aa 1 select oref, a from t2 where a not in (select min(ie) from t1 where oref=t2.oref group by grp); oref a bb 2 ff 2 dd NULL update t1 set ie=3 where oref='ff' and ie=1; select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2; oref a Z ee NULL NULL bb 2 0 ff 2 1 cc 3 NULL aa 1 1 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select min(ie) from t1 where oref=t2.oref group by grp); oref a ff 2 aa 1 select oref, a from t2 where a not in (select min(ie) from t1 where oref=t2.oref group by grp); oref a bb 2 dd NULL select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1) Z from t2; oref a Z ee NULL 0 bb 2 0 ff 2 1 cc 3 0 aa 1 0 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1); oref a ff 2 select oref, a from t2 where a not in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1); oref a ee NULL bb 2 cc 3 aa 1 dd NULL alter table t1 add index idx(ie); explain select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 index_subquery idx idx 5 func 4 Using where; Full scan on NULL key select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; oref a Z ee NULL NULL bb 2 0 ff 2 1 cc 3 NULL aa 1 1 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select ie from t1 where oref=t2.oref); oref a ff 2 aa 1 select oref, a from t2 where a not in (select ie from t1 where oref=t2.oref); oref a bb 2 dd NULL alter table t1 drop index idx; alter table t1 add index idx(oref,ie); explain select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 ref_or_null idx idx 10 test.t2.oref,func 4 Using where; Using index; Full scan on NULL key select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; oref a Z ee NULL NULL bb 2 0 ff 2 1 cc 3 NULL aa 1 1 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select ie from t1 where oref=t2.oref); oref a ff 2 aa 1 select oref, a from t2 where a not in (select ie from t1 where oref=t2.oref); oref a bb 2 dd NULL explain select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 ref idx idx 5 test.t2.oref 2 Using where; Using temporary; Using filesort select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1) Z from t2; oref a Z ee NULL 0 bb 2 0 ff 2 1 cc 3 0 aa 1 0 dd NULL 0 bb NULL NULL select oref, a from t2 where a in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1); oref a ff 2 select oref, a from t2 where a not in (select min(ie) from t1 where oref=t2.oref group by grp having min(ie) > 1); oref a ee NULL bb 2 cc 3 aa 1 dd NULL drop table t1,t2; create table t1 (oref char(4), grp int, ie1 int, ie2 int); insert into t1 (oref, grp, ie1, ie2) values ('aa', 10, 2, 1), ('aa', 10, 1, 1), ('aa', 20, 2, 1), ('bb', 10, 3, 1), ('cc', 10, 4, 2), ('cc', 20, 3, 2), ('ee', 10, 2, 1), ('ee', 10, 1, 2), ('ff', 20, 2, 2), ('ff', 20, 1, 2); create table t2 (oref char(4), a int, b int); insert into t2 values ('ee', NULL, 1), ('bb', 2, 1), ('ff', 2, 2), ('cc', 3, NULL), ('bb', NULL, NULL), ('aa', 1, 1), ('dd', 1, NULL); select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2; oref a b Z ee NULL 1 NULL bb 2 1 0 ff 2 2 1 cc 3 NULL NULL bb NULL NULL NULL aa 1 1 1 dd 1 NULL 0 select oref, a, b from t2 where (a,b) in (select ie1,ie2 from t1 where oref=t2.oref); oref a b ff 2 2 aa 1 1 select oref, a, b from t2 where (a,b) not in (select ie1,ie2 from t1 where oref=t2.oref); oref a b bb 2 1 dd 1 NULL select oref, a, b, (a,b) in (select min(ie1),max(ie2) from t1 where oref=t2.oref group by grp) Z from t2; oref a b Z ee NULL 1 0 bb 2 1 0 ff 2 2 0 cc 3 NULL NULL bb NULL NULL NULL aa 1 1 1 dd 1 NULL 0 select oref, a, b from t2 where (a,b) in (select min(ie1), max(ie2) from t1 where oref=t2.oref group by grp); oref a b aa 1 1 select oref, a, b from t2 where (a,b) not in (select min(ie1), max(ie2) from t1 where oref=t2.oref group by grp); oref a b ee NULL 1 bb 2 1 ff 2 2 dd 1 NULL alter table t1 add index idx(ie1,ie2); explain select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 index_subquery idx idx 5 func 4 Using where; Full scan on NULL key select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2; oref a b Z ee NULL 1 NULL bb 2 1 0 ff 2 2 1 cc 3 NULL NULL bb NULL NULL NULL aa 1 1 1 dd 1 NULL 0 select oref, a, b from t2 where (a,b) in (select ie1,ie2 from t1 where oref=t2.oref); oref a b ff 2 2 aa 1 1 select oref, a, b from t2 where (a,b) not in (select ie1,ie2 from t1 where oref=t2.oref); oref a b bb 2 1 dd 1 NULL explain extended select oref, a, b, (a,b) in (select ie1,ie2 from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows filtered Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 100.00 2 DEPENDENT SUBQUERY t1 index_subquery idx idx 5 func 4 100.00 Using where; Full scan on NULL key Warnings: Note 1276 Field or reference 'test.t2.oref' of SELECT #2 was resolved in SELECT #1 Note 1003 select `test`.`t2`.`oref` AS `oref`,`test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b`,<in_optimizer>((`test`.`t2`.`a`,`test`.`t2`.`b`),<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on idx checking NULL where ((`test`.`t1`.`oref` = `test`.`t2`.`oref`) and trigcond(((<cache>(`test`.`t2`.`a`) = `test`.`t1`.`ie1`) or isnull(`test`.`t1`.`ie1`))) and trigcond(((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`ie2`) or isnull(`test`.`t1`.`ie2`)))) having (trigcond(<is_not_null_test>(`test`.`t1`.`ie1`)) and trigcond(<is_not_null_test>(`test`.`t1`.`ie2`)))))) AS `Z` from `test`.`t2` drop table t1,t2; create table t1 (oref char(4), grp int, ie int primary key); insert into t1 (oref, grp, ie) values ('aa', 10, 2), ('aa', 10, 1), ('bb', 10, 3), ('cc', 10, 4), ('cc', 20, 5), ('cc', 10, 6); create table t2 (oref char(4), a int); insert into t2 values ('ee', NULL), ('bb', 2), ('cc', 5), ('cc', 2), ('cc', NULL), ('aa', 1), ('bb', NULL); explain select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 unique_subquery PRIMARY PRIMARY 4 func 1 Using where; Full scan on NULL key select oref, a, a in (select ie from t1 where oref=t2.oref) Z from t2; oref a Z ee NULL 0 bb 2 0 cc 5 1 cc 2 0 cc NULL NULL aa 1 1 bb NULL NULL select oref, a from t2 where a in (select ie from t1 where oref=t2.oref); oref a cc 5 aa 1 select oref, a from t2 where a not in (select ie from t1 where oref=t2.oref); oref a ee NULL bb 2 cc 2 explain select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2; id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 7 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 6 Using where; Using temporary; Using filesort select oref, a, a in (select min(ie) from t1 where oref=t2.oref group by grp) Z from t2; oref a Z ee NULL 0 bb 2 0 cc 5 1 cc 2 0 cc NULL NULL aa 1 1 bb NULL NULL drop table t1,t2; create table t1 (a int, b int); insert into t1 values (0,0), (2,2), (3,3); create table t2 (a int, b int); insert into t2 values (1,1), (3,3); select a, b, (a,b) in (select a, min(b) from t2 group by a) Z from t1; a b Z 0 0 0 2 2 0 3 3 1 insert into t2 values (NULL,4); select a, b, (a,b) in (select a, min(b) from t2 group by a) Z from t1; a b Z 0 0 0 2 2 0 3 3 1 drop table t1,t2; CREATE TABLE t1 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b)); INSERT INTO t1 VALUES (1,1,'a'), (1,2,'b'), (1,3,'c'), (1,4,'d'), (1,5,'e'), (2,1,'f'), (2,2,'g'), (2,3,'h'), (3,4,'i'),(3,3,'j'), (3,2,'k'), (3,1,'l'), (1,9,'m'); CREATE TABLE t2 (a int, b INT, c CHAR(10) NOT NULL, PRIMARY KEY (a, b)); INSERT INTO t2 SELECT * FROM t1; SELECT a, MAX(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b)) as test FROM t1 GROUP BY a; a MAX(b) test 1 9 m 2 3 h 3 4 i SELECT * FROM t1 GROUP by t1.a HAVING (MAX(t1.b) > (SELECT MAX(t2.b) FROM t2 WHERE t2.c < t1.c HAVING MAX(t2.b+t1.a) < 10)); a b c SELECT a,b,c FROM t1 WHERE b in (9,3,4) ORDER BY b,c; a b c 1 3 c 2 3 h 3 3 j 1 4 d 3 4 i 1 9 m SELECT a, MAX(b), (SELECT COUNT(DISTINCT t.c) FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as cnt, (SELECT t.b FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as t_b, (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as t_b, (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) ORDER BY t.c LIMIT 1) as t_b FROM t1 GROUP BY a; a MAX(b) cnt t_b t_b t_b 1 9 1 9 m m 2 3 1 3 h h 3 4 1 4 i i SELECT a, MAX(b), (SELECT t.c FROM t1 AS t WHERE t1.a=t.a AND t.b=MAX(t1.b) LIMIT 1) as test FROM t1 GROUP BY a; a MAX(b) test 1 9 m 2 3 h 3 4 i DROP TABLE t1, t2; CREATE TABLE t1 (a int); CREATE TABLE t2 (b int, PRIMARY KEY(b)); INSERT INTO t1 VALUES (1), (NULL), (4); INSERT INTO t2 VALUES (3), (1),(2), (5), (4), (7), (6); EXPLAIN EXTENDED SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1)); 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 1 PRIMARY t2 eq_ref PRIMARY PRIMARY 4 test.t1.a 1 100.00 Using index 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 100.00 Using where Warnings: Note 1003 select `test`.`t1`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`b` = `test`.`t1`.`a`) and (not(<in_optimizer>(`test`.`t1`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` where ((<cache>(`test`.`t2`.`b`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)) having <is_not_null_test>(`test`.`t1`.`a`)))))) SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1)); a SELECT a FROM t1, t2 WHERE a=b AND (b NOT IN (SELECT a FROM t1 WHERE a > 4)); a 1 4 DROP TABLE t1,t2; CREATE TABLE t1 (id int); CREATE TABLE t2 (id int PRIMARY KEY); CREATE TABLE t3 (id int PRIMARY KEY, name varchar(10)); INSERT INTO t1 VALUES (2), (NULL), (3), (1); INSERT INTO t2 VALUES (234), (345), (457); INSERT INTO t3 VALUES (222,'bbb'), (333,'ccc'), (111,'aaa'); EXPLAIN SELECT * FROM t1 WHERE t1.id NOT IN (SELECT t2.id FROM t2,t3 WHERE t3.name='xxx' AND t2.id=t3.id); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 ALL NULL NULL NULL NULL 4 Using where 2 DEPENDENT SUBQUERY t2 eq_ref PRIMARY PRIMARY 4 func 1 Using where; Using index; Full scan on NULL key 2 DEPENDENT SUBQUERY t3 eq_ref PRIMARY PRIMARY 4 func 1 Using where; Full scan on NULL key SELECT * FROM t1 WHERE t1.id NOT IN (SELECT t2.id FROM t2,t3 WHERE t3.name='xxx' AND t2.id=t3.id); id 2 NULL 3 1 SELECT (t1.id IN (SELECT t2.id FROM t2,t3 WHERE t3.name='xxx' AND t2.id=t3.id)) AS x FROM t1; x 0 0 0 0 DROP TABLE t1,t2,t3; CREATE TABLE t1 (a INT NOT NULL); INSERT INTO t1 VALUES (1),(-1), (65),(66); CREATE TABLE t2 (a INT UNSIGNED NOT NULL PRIMARY KEY); INSERT INTO t2 VALUES (65),(66); SELECT a FROM t1 WHERE a NOT IN (65,66); a 1 -1 SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2); a 1 -1 EXPLAIN SELECT a FROM t1 WHERE a NOT IN (SELECT a FROM t2); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t1 ALL NULL NULL NULL NULL 4 Using where 2 DEPENDENT SUBQUERY t2 unique_subquery PRIMARY PRIMARY 4 func 1 Using index; Using where DROP TABLE t1, t2; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES(1); CREATE TABLE t2 (placeholder CHAR(11)); INSERT INTO t2 VALUES("placeholder"); SELECT ROW(1, 2) IN (SELECT t1.a, 2) FROM t1 GROUP BY t1.a; ROW(1, 2) IN (SELECT t1.a, 2) 1 SELECT ROW(1, 2) IN (SELECT t1.a, 2 FROM t2) FROM t1 GROUP BY t1.a; ROW(1, 2) IN (SELECT t1.a, 2 FROM t2) 1 DROP TABLE t1, t2; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2),(3); CREATE TABLE t2 SELECT * FROM t1; SELECT 1 FROM t1 WHERE t1.a NOT IN (SELECT 1 FROM t1, t2 WHERE 0); 1 1 1 1 DROP TABLE t1, t2; CREATE TABLE t1 ( pk INT PRIMARY KEY, int_key INT, varchar_key VARCHAR(5) UNIQUE, varchar_nokey VARCHAR(5) ); INSERT INTO t1 VALUES (9, 7,NULL,NULL), (10,8,'p' ,'p'); SELECT varchar_nokey FROM t1 WHERE NULL NOT IN ( SELECT INNR.pk FROM t1 AS INNR2 LEFT JOIN t1 AS INNR ON ( INNR2.int_key = INNR.int_key ) WHERE INNR.varchar_key > 'n{' ); varchar_nokey DROP TABLE t1; End of 5.0 tests create table t0 (a int); insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); create table t1 ( a int(11) default null, b int(11) default null, key (a) ); insert into t1 select A.a+10*(B.a+10*C.a),A.a+10*(B.a+10*C.a) from t0 A, t0 B, t0 C; create table t2 (a int(11) default null); insert into t2 values (0),(1); create table t3 (a int(11) default null); insert into t3 values (0),(1); create table t4 (a int(11) default null); insert into t4 values (0),(1); create table t5 (a int(11) default null); insert into t5 values (0),(1),(0),(1); select * from t2, t3 where t2.a < 10 and t3.a+1 = 2 and t3.a in (select t1.b from t1 where t1.a+1=t1.a+1 and t1.a < (select t4.a+10 from t4, t5 limit 2)); ERROR 21000: Subquery returns more than 1 row drop table t0, t1, t2, t3, t4, t5;