drop table if exists t0, t1, t2, t3, t4;
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 '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 '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 '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 '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 '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 '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
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`.`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 '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 '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;
