mariadb/mysql-test/r/subselect_mat_cost.result

drop table if exists t1, t2, t1_1024, t2_1024;
drop procedure if exists make_t1_indexes;
drop procedure if exists make_t2_indexes;
drop procedure if exists remove_t1_indexes;
drop procedure if exists remove_t2_indexes;
drop procedure if exists add_materialization_data;
drop procedure if exists delete_materialization_data;
drop procedure if exists set_all_columns_not_null;
drop procedure if exists set_all_columns_nullable;
create table t1 (a1 char(8), a2 char(8), a3 char(8), a4 int);
insert into t1 values ('1 - 00', '2 - 00', '3 - 00', 0);
insert into t1 values ('1 - 01', '2 - 01', '3 - 01', 1);
insert into t1 values ('1 - 02', '2 - 02', '3 - 02', 2);
create table t2 (b1 char(8), b2 char(8), b3 char(8), b4 int);
insert into t2 values ('1 - 01', '2 - 01', '3 - 01', 1);
insert into t2 values ('1 - 01', '2 - 01', '3 - 02', 2);
insert into t2 values ('1 - 02', '2 - 02', '3 - 03', 3);
insert into t2 values ('1 - 02', '2 - 02', '3 - 04', 4);
insert into t2 values ('1 - 03', '2 - 03', '3 - 05', 5);
create table t1_1024 (a1 blob(1024), a2 blob(1024));
insert into t1_1024 values (concat('1 - 00', repeat('x', 1018)), concat('2 - 00', repeat('x', 1018)));
insert into t1_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
create table t2_1024 (b1 blob(1024), b2 blob(1024));
insert into t2_1024 values (concat('1 - 01', repeat('x', 1018)), concat('2 - 01', repeat('x', 1018)));
insert into t2_1024 values (concat('1 - 02', repeat('x', 1018)), concat('2 - 02', repeat('x', 1018)));
insert into t2_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
insert into t2_1024 values (concat('1 - 04', repeat('x', 1018)), concat('2 - 04', repeat('x', 1018)));
create procedure make_t1_indexes()
begin
create index it1i1 on t1 (a1);
create index it1i2 on t1 (a2);
create index it1i3 on t1 (a1, a2);
create index it1_1024i1 on t1_1024 (a1(6));
create index it1_1024i2 on t1_1024 (a2(6));
create index it1_1024i3 on t1_1024 (a1(6), a2(6));
end|
create procedure make_t2_indexes()
begin
create index it2i1 on t2 (b1);
create index it2i2 on t2 (b2);
create index it2i3 on t2 (b1, b2);
create unique index it2i4 on t2 (b1, b2, b3);
create index it2_1024i1 on t2_1024 (b1(6));
create index it2_1024i2 on t2_1024 (b2(6));
create index it2_1024i3 on t2_1024 (b1(6), b2(6));
end|
create procedure remove_t1_indexes()
begin
drop index it1i1 on t1;
drop index it1i2 on t1;
drop index it1i3 on t1;
drop index it1_1024i1 on t1_1024;
drop index it1_1024i2 on t1_1024;
drop index it1_1024i3 on t1_1024;
end|
create procedure remove_t2_indexes()
begin
drop index it2i1 on t2;
drop index it2i2 on t2;
drop index it2i3 on t2;
drop index it2i4 on t2;
drop index it2_1024i1 on t2_1024;
drop index it2_1024i2 on t2_1024;
drop index it2_1024i3 on t2_1024;
end|
create procedure add_materialization_data()
begin
insert into t1 values ('1 - 03', '2 - 03', '3 - 03', 3);
insert into t1 values ('1 - 04', '2 - 04', '3 - 04', 4);
insert into t1 values ('1 - 05', '2 - 05', '3 - 05', 5);
insert into t1 values ('1 - 06', '2 - 06', '3 - 06', 6);
insert into t1 values ('1 - 07', '2 - 07', '3 - 07', 7);
insert into t1_1024 values (concat('1 - 03', repeat('x', 1018)), concat('2 - 03', repeat('x', 1018)));
end|
create procedure delete_materialization_data()
begin
delete from t1 where a1 >= '1 - 03';
delete from t1_1024 where a1 >= '1 - 03';
end|
create procedure set_all_columns_not_null()
begin
alter table t1 modify a1 char(8) not null, modify a2 char(8) not null, modify a3 char(8) not null;
alter table t2 modify b1 char(8) not null, modify b2 char(8) not null, modify b3 char(8) not null;
end|
create procedure set_all_columns_nullable()
begin
alter table t1 modify a1 char(8) null, modify a2 char(8) null, modify a3 char(8) null;
alter table t2 modify b1 char(8) null, modify b2 char(8) null, modify b3 char(8) null;
end|

/******************************************************************************
1. Both materialization and in-to-exists are ON, make a cost-based choice.
******************************************************************************/
set @@optimizer_switch='materialization=on,in_to_exists=on';

/* 1.1 In-to-exists is cheaper */
call make_t1_indexes();
/* 1.1.1 non-indexed table access */

/* 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	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	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

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	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	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

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	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	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	index	NULL	it1i3	18	NULL	3	Using where; Using index
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

/* 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	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	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

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	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	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	3	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	3	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	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	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;
#
# LP BUG#714808 Assertion `outer_lookup_keys <= outer_record_count'
# failed with materialization
CREATE TABLE t1 ( pk int(11), PRIMARY KEY (pk)) ;
CREATE TABLE t2 ( f2 int(11)) ;
CREATE TABLE t3 ( f1 int(11), f3 varchar(1), KEY (f1)) ;
INSERT INTO t3 VALUES (7,'f');
set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
EXPLAIN
SELECT t1.*
FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
SELECT t1.*
FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
pk
drop table t1,t2,t3;
#
# LP BUG#714999 Second crash in select_describe() with nested subqueries
#
CREATE TABLE t1 ( pk int(11)) ;
INSERT INTO t1 VALUES (29);
CREATE TABLE t2 ( f1 varchar(1)) ;
INSERT INTO t2 VALUES ('f'),('d');
CREATE TABLE t3 ( f2 varchar(1)) ;
EXPLAIN SELECT f2 FROM t3 WHERE (
SELECT MAX( pk ) FROM t1
WHERE EXISTS (
SELECT DISTINCT f1
FROM t2
)
) IS NULL ;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	
3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using temporary
drop table t1, t2;
#
# LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
#
CREATE TABLE t2 ( f2 int(11)) ;
CREATE TABLE t1 ( f3 int(11), KEY (f3)) ;
INSERT INTO t1 VALUES (6),(4);
EXPLAIN
SELECT * FROM (SELECT * FROM t2) AS a2
WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
insert into t2 values (1),(2);
EXPLAIN
SELECT * FROM (SELECT * FROM t2) AS a2
WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2