drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t11,t12;
select (select 2);
(select 2)
2
explain extended select (select 2);
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
Warnings:
Note	1249	Select 2 was reduced during optimisation
Note	1003	select 2 AS `(select 2)`
SELECT (SELECT 1) UNION SELECT (SELECT 2);
(SELECT 1)
1
2
explain extended SELECT (SELECT 1) UNION SELECT (SELECT 2);
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
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union1,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1249	Select 2 was reduced during optimisation
Note	1249	Select 4 was reduced during optimisation
Note	1003	select 1 AS `(SELECT 1)` union select 2 AS `(SELECT 2)`
SELECT (SELECT (SELECT 0 UNION SELECT 0));
(SELECT (SELECT 0 UNION SELECT 0))
0
explain extended SELECT (SELECT (SELECT 0 UNION SELECT 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
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
4	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1249	Select 2 was reduced during optimisation
Note	1003	select (select 0 AS `0` union select 0 AS `0`) AS `(SELECT (SELECT 0 UNION SELECT 0))`
SELECT (SELECT 1 FROM (SELECT 1) as b HAVING a=1) as a;
ERROR 42S22: Reference 'a' not supported (forward reference in item list)
SELECT (SELECT 1 FROM (SELECT 1) as b HAVING b=1) as a,(SELECT 1 FROM (SELECT 1) as c HAVING a=1) as b;
ERROR 42S22: Reference 'b' not supported (forward reference in item list)
SELECT (SELECT 1),MAX(1) FROM (SELECT 1) as a;
(SELECT 1)	MAX(1)
1	1
SELECT (SELECT a) as a;
ERROR 42S22: Reference 'a' not supported (forward reference in item list)
EXPLAIN EXTENDED SELECT 1 FROM (SELECT 1 as a) as b  HAVING (SELECT a)=1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1276	Field or reference 'a' of SELECT #3 was resolved in SELECT #1
Note	1276	Field or reference 'b.a' of SELECT #3 was resolved in SELECT #1
Note	1003	select 1 AS `1` from (select 1 AS `a`) b having ((select b.a AS `a`) = 1)
SELECT 1 FROM (SELECT 1 as a) as b HAVING (SELECT a)=1;
1
1
SELECT (SELECT 1), a;
ERROR 42S22: Unknown column 'a' in 'checking transformed subquery'
SELECT 1 as a FROM (SELECT 1) as b HAVING (SELECT a)=1;
a
1
SELECT 1 FROM (SELECT (SELECT a) b) c;
ERROR 42S22: Unknown column 'a' in 'field list'
SELECT * FROM (SELECT 1 as id) b WHERE id IN (SELECT * FROM (SELECT 1 as id) c ORDER BY id);
id
1
SELECT * FROM (SELECT 1) a  WHERE 1 IN (SELECT 1,1);
ERROR 21000: Operand should contain 1 column(s)
SELECT 1 IN (SELECT 1);
1 IN (SELECT 1)
1
SELECT 1 FROM (SELECT 1 as a) b WHERE 1 IN (SELECT (SELECT a));
1
1
select (SELECT 1 FROM (SELECT 1) a PROCEDURE ANALYSE(1));
ERROR HY000: Wrong usage of PROCEDURE and subquery
SELECT 1 FROM (SELECT 1) a PROCEDURE ANALYSE((SELECT 1));
ERROR HY000: Incorrect parameters to procedure 'ANALYSE'
SELECT (SELECT 1) as a FROM (SELECT 1) b WHERE (SELECT a) IS NULL;
a
SELECT (SELECT 1) as a FROM (SELECT 1) b WHERE (SELECT a) IS NOT NULL;
a
1
SELECT (SELECT 1,2,3) = ROW(1,2,3);
(SELECT 1,2,3) = ROW(1,2,3)
1
SELECT (SELECT 1,2,3) = ROW(1,2,1);
(SELECT 1,2,3) = ROW(1,2,1)
0
SELECT (SELECT 1,2,3) < ROW(1,2,1);
(SELECT 1,2,3) < ROW(1,2,1)
0
SELECT (SELECT 1,2,3) > ROW(1,2,1);
(SELECT 1,2,3) > ROW(1,2,1)
1
SELECT (SELECT 1,2,3) = ROW(1,2,NULL);
(SELECT 1,2,3) = ROW(1,2,NULL)
NULL
SELECT ROW(1,2,3) = (SELECT 1,2,3);
ROW(1,2,3) = (SELECT 1,2,3)
1
SELECT ROW(1,2,3) = (SELECT 1,2,1);
ROW(1,2,3) = (SELECT 1,2,1)
0
SELECT ROW(1,2,3) < (SELECT 1,2,1);
ROW(1,2,3) < (SELECT 1,2,1)
0
SELECT ROW(1,2,3) > (SELECT 1,2,1);
ROW(1,2,3) > (SELECT 1,2,1)
1
SELECT ROW(1,2,3) = (SELECT 1,2,NULL);
ROW(1,2,3) = (SELECT 1,2,NULL)
NULL
SELECT (SELECT 1.5,2,'a') = ROW(1.5,2,'a');
(SELECT 1.5,2,'a') = ROW(1.5,2,'a')
1
SELECT (SELECT 1.5,2,'a') = ROW(1.5,2,'b');
(SELECT 1.5,2,'a') = ROW(1.5,2,'b')
0
SELECT (SELECT 1.5,2,'a') = ROW('b',2,'b');
(SELECT 1.5,2,'a') = ROW('b',2,'b')
0
SELECT (SELECT 'b',2,'a') = ROW(1.5,2,'a');
(SELECT 'b',2,'a') = ROW(1.5,2,'a')
0
SELECT (SELECT 1.5,2,'a') = ROW(1.5,'c','a');
(SELECT 1.5,2,'a') = ROW(1.5,'c','a')
0
SELECT (SELECT 1.5,'c','a') = ROW(1.5,2,'a');
(SELECT 1.5,'c','a') = ROW(1.5,2,'a')
0
SELECT (SELECT * FROM (SELECT 'test' a,'test' b) a);
ERROR 21000: Operand should contain 1 column(s)
SELECT 1 as a,(SELECT a+a) b,(SELECT b);
a	b	(SELECT b)
1	2	2
create table t1 (a int);
create table t2 (a int, b int);
create table t3 (a int);
create table t4 (a int not null, b int not null);
insert into t1 values (2);
insert into t2 values (1,7),(2,7);
insert into t4 values (4,8),(3,8),(5,9);
select (select a from t1 where t1.a = a1) as a2, (select b from t2 where t2.b=a2) as a1;
ERROR 42S22: Reference 'a1' not supported (forward reference in item list)
select (select a from t1 where t1.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a)	a
NULL	1
2	2
select (select a from t1 where t1.a=t2.b), a from t2;
(select a from t1 where t1.a=t2.b)	a
NULL	1
NULL	2
select (select a from t1), a, (select 1 union select 2 limit 1) from t2;
(select a from t1)	a	(select 1 union select 2 limit 1)
2	1	1
2	2	1
select (select a from t3), a from t2;
(select a from t3)	a
NULL	1
NULL	2
select * from t2 where t2.a=(select a from t1);
a	b
2	7
insert into t3 values (6),(7),(3);
select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1);
a	b
1	7
2	7
(select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)) union (select * from t4 order by a limit 2) limit 3;
a	b
1	7
2	7
3	8
(select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)) union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
a	b
1	7
2	7
3	8
4	8
explain extended (select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)) union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	Using filesort
3	UNION	t4	ALL	NULL	NULL	NULL	NULL	3	Using where; Using filesort
4	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
NULL	UNION RESULT	<union1,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	(select test.t2.a AS `a`,test.t2.b AS `b` from test.t2 where (test.t2.b = (select test.t3.a AS `a` from test.t3 order by test.t3.a desc limit 1))) union (select test.t4.a AS `a`,test.t4.b AS `b` from test.t4 where (test.t4.b = (select (max(test.t2.a) * 4) AS `max(t2.a)*4` from test.t2)) order by test.t4.a)
select (select a from t3 where a<t2.a*4 order by 1 desc limit 1), a from t2;
(select a from t3 where a<t2.a*4 order by 1 desc limit 1)	a
3	1
7	2
select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from 
(select * from t2 where a>1) as tt;
(select t3.a from t3 where a<8 order by 1 desc limit 1)	a
7	2
explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from 
(select * from t2 where a>1) as tt;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived3>	system	NULL	NULL	NULL	NULL	1	
3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where; Using filesort
Warnings:
Note	1003	select (select test.t3.a AS `a` from test.t3 where (test.t3.a < 8) order by test.t3.a desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,tt.a AS `a` from (select test.t2.a AS `a`,test.t2.b AS `b` from test.t2 where (test.t2.a > 1)) tt
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
a
2
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a > t1.a) order by 1 desc limit 1);
a
2
select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a < t1.a) order by 1 desc limit 1);
a
select b,(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2) from t4;
b	(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2)
8	7.5000
8	4.5000
9	7.5000
explain extended select b,(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2) from t4;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	3	
2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1276	Field or reference 't4.a' of SELECT #3 was resolved in SELECT #1
Note	1003	select test.t4.b AS `b`,(select avg((test.t2.a + (select min(test.t3.a) AS `min(t3.a)` from test.t3 where (test.t3.a >= test.t4.a)))) AS `avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a))` from test.t2) AS `(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2)` from test.t4
select * from t3 where exists (select * from t2 where t2.b=t3.a);
a
7
select * from t3 where not exists (select * from t2 where t2.b=t3.a);
a
6
3
select * from t3 where a in (select b from t2);
a
7
select * from t3 where a not in (select b from t2);
a
6
3
select * from t3 where a = some (select b from t2);
a
7
select * from t3 where a <> any (select b from t2);
a
6
3
select * from t3 where a = all (select b from t2);
a
7
select * from t3 where a <> all (select b from t2);
a
6
3
insert into t2 values (100, 5);
select * from t3 where a < any (select b from t2);
a
6
3
select * from t3 where a < all (select b from t2);
a
3
select * from t3 where a >= any (select b from t2);
a
6
7
explain extended select * from t3 where a >= any (select b from t2);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	3	
Warnings:
Note	1003	select test.t3.a AS `a` from test.t3 where (test.t3.a >= (select min(test.t2.b) from test.t2))
select * from t3 where a >= all (select b from t2);
a
7
delete from t2 where a=100;
select * from t3 where a in (select a,b from t2);
ERROR 21000: Operand should contain 1 column(s)
select * from t3 where a in (select * from t2);
ERROR 21000: Operand should contain 1 column(s)
insert into t4 values (12,7),(1,7),(10,9),(9,6),(7,6),(3,9),(1,10);
select b,max(a) as ma from t4 group by b having b < (select max(t2.a) from t2 where t2.b=t4.b);
b	ma
insert into t2 values (2,10);
select b,max(a) as ma from t4 group by b having ma < (select max(t2.a) from t2 where t2.b=t4.b);
b	ma
10	1
delete from t2 where a=2 and b=10;
select b,max(a) as ma from t4 group by b having b >= (select max(t2.a) from t2 where t2.b=t4.b);
b	ma
7	12
create table t5 (a int);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
insert into t5 values (5);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
insert into t5 values (2);
select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)	a
NULL	1
2	2
explain extended select (select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a), a from t2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
2	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	
3	DEPENDENT UNION	t5	ALL	NULL	NULL	NULL	NULL	2	Using where
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1276	Field or reference 't2.a' of SELECT #2 was resolved in SELECT #1
Note	1276	Field or reference 't2.a' of SELECT #3 was resolved in SELECT #1
Note	1003	select (select test.t1.a AS `a` from test.t1 where (test.t1.a = test.t2.a) union select test.t5.a AS `a` from test.t5 where (test.t5.a = test.t2.a)) AS `(select a from t1 where t1.a=t2.a union select a from t5 where t5.a=t2.a)`,test.t2.a AS `a` from test.t2
select (select a from t1 where t1.a=t2.a union all select a from t5 where t5.a=t2.a), a from t2;
ERROR 21000: Subquery returns more than 1 row
create table t6 (patient_uq int, clinic_uq int, index i1 (clinic_uq));
create table t7( uq int primary key, name char(25));
insert into t7 values(1,"Oblastnaia bolnitsa"),(2,"Bolnitsa Krasnogo Kresta");
insert into t6 values (1,1),(1,2),(2,2),(1,3);
select * from t6 where exists (select * from t7 where uq = clinic_uq);
patient_uq	clinic_uq
1	1
1	2
2	2
explain extended select * from t6 where exists (select * from t7 where uq = clinic_uq);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t6	ALL	NULL	NULL	NULL	NULL	4	Using where
2	DEPENDENT SUBQUERY	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.clinic_uq	1	Using index
Warnings:
Note	1276	Field or reference 'clinic_uq' of SELECT #2 was resolved in SELECT #1
Note	1003	select test.t6.patient_uq AS `patient_uq`,test.t6.clinic_uq AS `clinic_uq` from test.t6 where exists(select 1 AS `Not_used` from test.t7 where (test.t7.uq = test.t6.clinic_uq))
select * from t1 where a= (select a from t2,t4 where t2.b=t4.b);
ERROR 23000: Column: 'a' in field list is ambiguous
drop table t1,t2,t3;
CREATE TABLE t3 (a varchar(20),b char(1) NOT NULL default '0');
INSERT INTO t3 VALUES ('W','a'),('A','c'),('J','b');
CREATE TABLE t2 (a varchar(20),b int NOT NULL default '0');
INSERT INTO t2 VALUES ('W','1'),('A','3'),('J','2');
CREATE TABLE t1 (a varchar(20),b date NOT NULL default '0000-00-00');
INSERT INTO t1 VALUES ('W','1732-02-22'),('A','1735-10-30'),('J','1743-04-13');
SELECT * FROM t1 WHERE b = (SELECT MIN(b) FROM t1);
a	b
W	1732-02-22
SELECT * FROM t2 WHERE b = (SELECT MIN(b) FROM t2);
a	b
W	1
SELECT * FROM t3 WHERE b = (SELECT MIN(b) FROM t3);
a	b
W	a
CREATE TABLE `t8` (
`pseudo` varchar(35) character set latin1 NOT NULL default '',
`email` varchar(60) character set latin1 NOT NULL default '',
PRIMARY KEY  (`pseudo`),
UNIQUE KEY `email` (`email`)
) ENGINE=MyISAM CHARSET=latin1 ROW_FORMAT=DYNAMIC;
INSERT INTO t8 (pseudo,email) VALUES ('joce','test');
INSERT INTO t8 (pseudo,email) VALUES ('joce1','test1');
INSERT INTO t8 (pseudo,email) VALUES ('2joce1','2test1');
EXPLAIN EXTENDED SELECT pseudo,(SELECT email FROM t8 WHERE pseudo=(SELECT pseudo FROM t8 WHERE pseudo='joce')) FROM t8 WHERE pseudo=(SELECT pseudo FROM t8 WHERE pseudo='joce');
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t8	const	PRIMARY	PRIMARY	35	const	1	Using index
4	SUBQUERY	t8	const	PRIMARY	PRIMARY	35		1	Using index
2	SUBQUERY	t8	const	PRIMARY	PRIMARY	35	const	1	
3	SUBQUERY	t8	const	PRIMARY	PRIMARY	35		1	Using index
Warnings:
Note	1003	select test.t8.pseudo AS `pseudo`,(select test.t8.email AS `email` from test.t8 where (test.t8.pseudo = (select test.t8.pseudo AS `pseudo` from test.t8 where (test.t8.pseudo = _latin1'joce')))) AS `(SELECT email FROM t8 WHERE pseudo=(SELECT pseudo FROM t8 WHERE pseudo='joce'))` from test.t8 where (test.t8.pseudo = (select test.t8.pseudo AS `pseudo` from test.t8 where (test.t8.pseudo = _latin1'joce')))
SELECT pseudo FROM t8 WHERE pseudo=(SELECT pseudo,email FROM
t8 WHERE pseudo='joce');
ERROR 21000: Operand should contain 1 column(s)
SELECT pseudo FROM t8 WHERE pseudo=(SELECT * FROM t8 WHERE
pseudo='joce');
ERROR 21000: Operand should contain 1 column(s)
SELECT pseudo FROM t8 WHERE pseudo=(SELECT pseudo FROM t8 WHERE pseudo='joce');
pseudo
joce
SELECT pseudo FROM t8 WHERE pseudo=(SELECT pseudo FROM t8 WHERE pseudo LIKE '%joce%');
ERROR 21000: Subquery returns more than 1 row
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8;
CREATE TABLE `t1` (
`topic` mediumint(8) unsigned NOT NULL default '0',
`date` date NOT NULL default '0000-00-00',
`pseudo` varchar(35) character set latin1 NOT NULL default '',
PRIMARY KEY  (`pseudo`,`date`,`topic`),
KEY `topic` (`topic`)
) ENGINE=MyISAM ROW_FORMAT=DYNAMIC;
INSERT INTO t1 (topic,date,pseudo) VALUES
('43506','2002-10-02','joce'),('40143','2002-08-03','joce');
EXPLAIN EXTENDED SELECT DISTINCT date FROM t1 WHERE date='2002-08-03';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	PRIMARY	41	NULL	2	Using where; Using index
Warnings:
Note	1003	select distinct test.t1.date AS `date` from test.t1 where (test.t1.date = 20020803)
EXPLAIN EXTENDED SELECT (SELECT DISTINCT date FROM t1 WHERE date='2002-08-03');
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	SUBQUERY	t1	index	NULL	PRIMARY	41	NULL	2	Using where; Using index
Warnings:
Note	1003	select (select distinct test.t1.date AS `date` from test.t1 where (test.t1.date = 20020803)) AS `(SELECT DISTINCT date FROM t1 WHERE date='2002-08-03')`
SELECT DISTINCT date FROM t1 WHERE date='2002-08-03';
date
2002-08-03
SELECT (SELECT DISTINCT date FROM t1 WHERE date='2002-08-03');
(SELECT DISTINCT date FROM t1 WHERE date='2002-08-03')
2002-08-03
SELECT 1 FROM t1 WHERE 1=(SELECT 1 UNION SELECT 1) UNION ALL SELECT 1;
1
1
1
1
SELECT 1 FROM t1 WHERE 1=(SELECT 1 UNION ALL SELECT 1) UNION SELECT 1;
ERROR 21000: Subquery returns more than 1 row
EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1=(SELECT 1 UNION SELECT 1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	topic	3	NULL	2	Using index
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	select 1 AS `1` from test.t1
drop table t1;
CREATE TABLE `t1` (
`numeropost` mediumint(8) unsigned NOT NULL auto_increment,
`maxnumrep` int(10) unsigned NOT NULL default '0',
PRIMARY KEY  (`numeropost`),
UNIQUE KEY `maxnumrep` (`maxnumrep`)
) ENGINE=MyISAM ROW_FORMAT=FIXED;
INSERT INTO t1 (numeropost,maxnumrep) VALUES (40143,1),(43506,2);
CREATE TABLE `t2` (
`mot` varchar(30) NOT NULL default '',
`topic` mediumint(8) unsigned NOT NULL default '0',
`date` date NOT NULL default '0000-00-00',
`pseudo` varchar(35) NOT NULL default '',
PRIMARY KEY  (`mot`,`pseudo`,`date`,`topic`)
) ENGINE=MyISAM ROW_FORMAT=DYNAMIC;
INSERT INTO t2 (mot,topic,date,pseudo) VALUES ('joce','40143','2002-10-22','joce'), ('joce','43506','2002-10-22','joce');
select numeropost as a FROM t1 GROUP BY (SELECT 1 FROM t1 HAVING a=1);
a
40143
SELECT numeropost,maxnumrep FROM t1 WHERE exists (SELECT 1 FROM t2 WHERE (mot='joce') AND date >= '2002-10-21' AND t1.numeropost = t2.topic) ORDER BY maxnumrep DESC LIMIT 0, 20;
numeropost	maxnumrep
43506	2
40143	1
SELECT (SELECT 1) as a FROM (SELECT 1 FROM t1 HAVING a=1) b;
ERROR 42S22: Unknown column 'a' in 'having clause'
SELECT 1 IN (SELECT 1 FROM t2 HAVING a);
ERROR 42S22: Unknown column 'a' in 'having clause'
SELECT * from t2 where topic IN (SELECT topic FROM t2 GROUP BY topic);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
joce	43506	2002-10-22	joce
SELECT * from t2 where topic IN (SELECT topic FROM t2 GROUP BY topic HAVING topic < 4100);
mot	topic	date	pseudo
SELECT * from t2 where topic IN (SELECT SUM(topic) FROM t1);
mot	topic	date	pseudo
SELECT * from t2 where topic = any (SELECT topic FROM t2 GROUP BY topic);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
joce	43506	2002-10-22	joce
SELECT * from t2 where topic = any (SELECT topic FROM t2 GROUP BY topic HAVING topic < 4100);
mot	topic	date	pseudo
SELECT * from t2 where topic = any (SELECT SUM(topic) FROM t1);
mot	topic	date	pseudo
SELECT * from t2 where topic = all (SELECT topic FROM t2 GROUP BY topic);
mot	topic	date	pseudo
SELECT * from t2 where topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 4100);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
joce	43506	2002-10-22	joce
SELECT *, topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 4100) from t2;
mot	topic	date	pseudo	topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 4100)
joce	40143	2002-10-22	joce	1
joce	43506	2002-10-22	joce	1
SELECT * from t2 where topic = all (SELECT SUM(topic) FROM t2);
mot	topic	date	pseudo
SELECT * from t2 where topic <> any (SELECT SUM(topic) FROM t2);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
joce	43506	2002-10-22	joce
SELECT * from t2 where topic IN (SELECT topic FROM t2 GROUP BY topic HAVING topic < 41000);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
SELECT * from t2 where topic = any (SELECT topic FROM t2 GROUP BY topic HAVING topic < 41000);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
SELECT * from t2 where topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 41000);
mot	topic	date	pseudo
joce	40143	2002-10-22	joce
SELECT *, topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 41000) from t2;
mot	topic	date	pseudo	topic = all (SELECT topic FROM t2 GROUP BY topic HAVING topic < 41000)
joce	40143	2002-10-22	joce	1
joce	43506	2002-10-22	joce	0
drop table t1,t2;
CREATE TABLE `t1` (
`numeropost` mediumint(8) unsigned NOT NULL auto_increment,
`maxnumrep` int(10) unsigned NOT NULL default '0',
PRIMARY KEY  (`numeropost`),
UNIQUE KEY `maxnumrep` (`maxnumrep`)
) ENGINE=MyISAM ROW_FORMAT=FIXED;
INSERT INTO t1 (numeropost,maxnumrep) VALUES (1,0),(2,1);
select numeropost as a FROM t1 GROUP BY (SELECT 1 FROM t1 HAVING a=1);
ERROR 21000: Subquery returns more than 1 row
select numeropost as a FROM t1 ORDER BY (SELECT 1 FROM t1 HAVING a=1);
ERROR 21000: Subquery returns more than 1 row
drop table t1;
create table t1 (a int);
insert into t1 values (1),(2),(3);
(select * from t1) union (select * from t1) order by (select a from t1 limit 1);
a
1
2
3
drop table t1;
CREATE TABLE t1 (field char(1) NOT NULL DEFAULT 'b');
INSERT INTO t1 VALUES ();
SELECT field FROM t1 WHERE 1=(SELECT 1 UNION ALL SELECT 1 FROM (SELECT 1) a HAVING field='b');
ERROR 21000: Subquery returns more than 1 row
drop table t1;
CREATE TABLE `t1` (
`numeropost` mediumint(8) unsigned NOT NULL default '0',
`numreponse` int(10) unsigned NOT NULL auto_increment,
`pseudo` varchar(35) NOT NULL default '',
PRIMARY KEY  (`numeropost`,`numreponse`),
UNIQUE KEY `numreponse` (`numreponse`),
KEY `pseudo` (`pseudo`,`numeropost`)
) ENGINE=MyISAM;
SELECT (SELECT numeropost FROM t1 HAVING numreponse=a),numreponse FROM (SELECT * FROM t1) as a;
ERROR 42S22: Reference 'numreponse' not supported (forward reference in item list)
SELECT numreponse, (SELECT numeropost FROM t1 HAVING numreponse=a) FROM (SELECT * FROM t1) as a;
ERROR 42S22: Unknown column 'a' in 'having clause'
SELECT numreponse, (SELECT numeropost FROM t1 HAVING numreponse=1) FROM (SELECT * FROM t1) as a;
numreponse	(SELECT numeropost FROM t1 HAVING numreponse=1)
INSERT INTO t1 (numeropost,numreponse,pseudo) VALUES (1,1,'joce'),(1,2,'joce'),(1,3,'test');
EXPLAIN EXTENDED SELECT numreponse FROM t1 WHERE numeropost='1' AND numreponse=(SELECT 1 FROM t1 WHERE numeropost='1');
ERROR 21000: Subquery returns more than 1 row
EXPLAIN EXTENDED SELECT MAX(numreponse) FROM t1 WHERE numeropost='1';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
Warnings:
Note	1003	select max(test.t1.numreponse) AS `MAX(numreponse)` from test.t1 where (test.t1.numeropost = _latin1'1')
EXPLAIN EXTENDED SELECT numreponse FROM t1 WHERE numeropost='1' AND numreponse=(SELECT MAX(numreponse) FROM t1 WHERE numeropost='1');
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	const	PRIMARY,numreponse	PRIMARY	7	const,const	1	Using index
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
Warnings:
Note	1003	select test.t1.numreponse AS `numreponse` from test.t1 where ((test.t1.numeropost = _latin1'1') and (test.t1.numreponse = 3))
drop table t1;
CREATE TABLE t1 (a int(1));
INSERT INTO t1 VALUES (1);
SELECT 1 FROM (SELECT a FROM t1) b HAVING (SELECT b.a)=1;
1
1
drop table t1;
create table t1 (a int NOT NULL, b int, primary key (a));
create table t2 (a int NOT NULL, b int, primary key (a));
insert into t1 values (0, 10),(1, 11),(2, 12);
insert into t2 values (1, 21),(2, 22),(3, 23);
select * from t1;
a	b
0	10
1	11
2	12
update t1 set b= (select b from t1);
ERROR HY000: You can't specify target table 't1' for update in FROM clause
update t1 set b= (select b from t2);
ERROR 21000: Subquery returns more than 1 row
update t1 set b= (select b from t2 where t1.a = t2.a);
select * from t1;
a	b
0	NULL
1	21
2	22
drop table t1, t2;
create table t1 (a int NOT NULL, b int, primary key (a));
create table t2 (a int NOT NULL, b int, primary key (a));
insert into t1 values (0, 10),(1, 11),(2, 12);
insert into t2 values (1, 21),(2, 12),(3, 23);
select * from t1;
a	b
0	10
1	11
2	12
select * from t1 where b = (select b from t2 where t1.a = t2.a);
a	b
2	12
delete from t1 where b = (select b from t1);
ERROR HY000: You can't specify target table 't1' for update in FROM clause
delete from t1 where b = (select b from t2);
ERROR 21000: Subquery returns more than 1 row
delete from t1 where b = (select b from t2 where t1.a = t2.a);
select * from t1;
a	b
0	10
1	11
drop table t1, t2;
create table t11 (a int NOT NULL, b int, primary key (a));
create table t12 (a int NOT NULL, b int, primary key (a));
create table t2 (a int NOT NULL, b int, primary key (a));
insert into t11 values (0, 10),(1, 11),(2, 12);
insert into t12 values (33, 10),(22, 11),(2, 12);
insert into t2 values (1, 21),(2, 12),(3, 23);
select * from t11;
a	b
0	10
1	11
2	12
select * from t12;
a	b
33	10
22	11
2	12
delete t11.*, t12.* from t11,t12 where t11.a = t12.a and t11.b = (select b from t12 where t11.a = t12.a);
ERROR HY000: You can't specify target table 't12' for update in FROM clause
delete t11.*, t12.* from t11,t12 where t11.a = t12.a and t11.b = (select b from t2);
ERROR 21000: Subquery returns more than 1 row
delete t11.*, t12.* from t11,t12 where t11.a = t12.a and t11.b = (select b from t2 where t11.a = t2.a);
select * from t11;
a	b
0	10
1	11
select * from t12;
a	b
33	10
22	11
drop table t11, t12, t2;
CREATE TABLE t1 (x int);
create table t2 (a int);
create table t3 (b int);
insert into t2 values (1);
insert into t3 values (1),(2);
INSERT INTO t1 (x) VALUES ((SELECT x FROM t1));
ERROR HY000: You can't specify target table 't1' for update in FROM clause
INSERT INTO t1 (x) VALUES ((SELECT b FROM t3));
ERROR 21000: Subquery returns more than 1 row
INSERT INTO t1 (x) VALUES ((SELECT a FROM t2));
select * from t1;
x
1
insert into t2 values (1);
INSERT DELAYED INTO t1 (x) VALUES ((SELECT SUM(a) FROM t2));
select * from t1;
x
1
2
INSERT INTO t1 (x) select (SELECT SUM(a)+1 FROM t2) FROM t2;
select * from t1;
x
1
2
3
3
INSERT INTO t1 (x) select (SELECT SUM(x)+2 FROM t1) FROM t2;
INSERT DELAYED INTO t1 (x) VALUES ((SELECT SUM(x) FROM t2));
ERROR 42S22: Unknown column 'x' in 'field list'
INSERT DELAYED INTO t1 (x) VALUES ((SELECT SUM(a) FROM t2));
select * from t1;
x
1
2
3
3
11
11
2
drop table t1, t2, t3;
CREATE TABLE t1 (x int not null, y int, primary key (x));
create table t2 (a int);
create table t3 (a int);
insert into t2 values (1);
insert into t3 values (1),(2);
select * from t1;
x	y
replace into t1 (x, y) VALUES ((SELECT x FROM t1), (SELECT a+1 FROM t2));
ERROR HY000: You can't specify target table 't1' for update in FROM clause
replace into t1 (x, y) VALUES ((SELECT a FROM t3), (SELECT a+1 FROM t2));
ERROR 21000: Subquery returns more than 1 row
replace into t1 (x, y) VALUES ((SELECT a FROM t2), (SELECT a+1 FROM t2));
select * from t1;
x	y
1	2
replace into t1 (x, y) VALUES ((SELECT a FROM t2), (SELECT a+2 FROM t2));
select * from t1;
x	y
1	3
replace DELAYED into t1 (x, y) VALUES ((SELECT a+3 FROM t2), (SELECT a FROM t2));
select * from t1;
x	y
1	3
4	1
replace DELAYED into t1 (x, y) VALUES ((SELECT a+3 FROM t2), (SELECT a+1 FROM t2));
select * from t1;
x	y
1	3
4	2
replace LOW_PRIORITY into t1 (x, y) VALUES ((SELECT a+1 FROM t2), (SELECT a FROM t2));
select * from t1;
x	y
1	3
4	2
2	1
drop table t1, t2, t3;
SELECT * FROM (SELECT 1) b WHERE 1 IN (SELECT *);
ERROR HY000: No tables used
CREATE TABLE t2 (id int(11) default NULL, KEY id (id)) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t2 VALUES (1),(2);
SELECT * FROM t2 WHERE id IN (SELECT 1);
id
1
EXPLAIN EXTENDED SELECT * FROM t2 WHERE id IN (SELECT 1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ref	id	id	5	const	1	Using where; Using index
Warnings:
Note	1249	Select 2 was reduced during optimisation
Note	1003	select test.t2.id AS `id` from test.t2 where (test.t2.id = 1)
SELECT * FROM t2 WHERE id IN (SELECT 1 UNION SELECT 3);
id
1
SELECT * FROM t2 WHERE id IN (SELECT 1+(select 1));
id
2
EXPLAIN EXTENDED SELECT * FROM t2 WHERE id IN (SELECT 1+(select 1));
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ref	id	id	5	const	1	Using where; Using index
Warnings:
Note	1249	Select 3 was reduced during optimisation
Note	1249	Select 2 was reduced during optimisation
Note	1003	select test.t2.id AS `id` from test.t2 where (test.t2.id = (1 + 1))
EXPLAIN EXTENDED SELECT * FROM t2 WHERE id IN (SELECT 1 UNION SELECT 3);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	id	5	NULL	2	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	
Warnings:
Note	1003	select test.t2.id AS `id` from test.t2 where <in_optimizer>(test.t2.id,<exists>(select 1 AS `Not_used` having (<cache>(test.t2.id) = <null_helper>(1)) union select 1 AS `Not_used` having (<cache>(test.t2.id) = <null_helper>(3))))
SELECT * FROM t2 WHERE id IN (SELECT 5 UNION SELECT 3);
id
SELECT * FROM t2 WHERE id IN (SELECT 5 UNION SELECT 2);
id
2
INSERT INTO t2 VALUES ((SELECT * FROM t2));
ERROR HY000: You can't specify target table 't2' for update in FROM clause
INSERT INTO t2 VALUES ((SELECT id FROM t2));
ERROR HY000: You can't specify target table 't2' for update in FROM clause
SELECT * FROM t2;
id
1
2
CREATE TABLE t1 (id int(11) default NULL, KEY id (id)) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 values (1),(1);
UPDATE t2 SET id=(SELECT * FROM t1);
ERROR 21000: Subquery returns more than 1 row
drop table t2, t1;
create table t1 (a int);
insert into t1 values (1),(2),(3);
select 1 IN (SELECT * from t1);
1 IN (SELECT * from t1)
1
select 10 IN (SELECT * from t1);
10 IN (SELECT * from t1)
0
select NULL IN (SELECT * from t1);
NULL IN (SELECT * from t1)
NULL
update t1 set a=NULL where a=2;
select 1 IN (SELECT * from t1);
1 IN (SELECT * from t1)
1
select 3 IN (SELECT * from t1);
3 IN (SELECT * from t1)
1
select 10 IN (SELECT * from t1);
10 IN (SELECT * from t1)
NULL
select 1 > ALL (SELECT * from t1);
1 > ALL (SELECT * from t1)
0
select 10 > ALL (SELECT * from t1);
10 > ALL (SELECT * from t1)
NULL
select 1 > ANY (SELECT * from t1);
1 > ANY (SELECT * from t1)
NULL
select 10 > ANY (SELECT * from t1);
10 > ANY (SELECT * from t1)
1
drop table t1;
create table t1 (a varchar(20));
insert into t1 values ('A'),('BC'),('DEF');
select 'A' IN (SELECT * from t1);
'A' IN (SELECT * from t1)
1
select 'XYZS' IN (SELECT * from t1);
'XYZS' IN (SELECT * from t1)
0
select NULL IN (SELECT * from t1);
NULL IN (SELECT * from t1)
NULL
update t1 set a=NULL where a='BC';
select 'A' IN (SELECT * from t1);
'A' IN (SELECT * from t1)
1
select 'DEF' IN (SELECT * from t1);
'DEF' IN (SELECT * from t1)
1
select 'XYZS' IN (SELECT * from t1);
'XYZS' IN (SELECT * from t1)
NULL
select 'A' > ALL (SELECT * from t1);
'A' > ALL (SELECT * from t1)
0
select 'XYZS' > ALL (SELECT * from t1);
'XYZS' > ALL (SELECT * from t1)
NULL
select 'A' > ANY (SELECT * from t1);
'A' > ANY (SELECT * from t1)
NULL
select 'XYZS' > ANY (SELECT * from t1);
'XYZS' > ANY (SELECT * from t1)
1
drop table t1;
create table t1 (a float);
insert into t1 values (1.5),(2.5),(3.5);
select 1.5 IN (SELECT * from t1);
1.5 IN (SELECT * from t1)
1
select 10.5 IN (SELECT * from t1);
10.5 IN (SELECT * from t1)
0
select NULL IN (SELECT * from t1);
NULL IN (SELECT * from t1)
NULL
update t1 set a=NULL where a=2.5;
select 1.5 IN (SELECT * from t1);
1.5 IN (SELECT * from t1)
1
select 3.5 IN (SELECT * from t1);
3.5 IN (SELECT * from t1)
1
select 10.5 IN (SELECT * from t1);
10.5 IN (SELECT * from t1)
NULL
select 1.5 > ALL (SELECT * from t1);
1.5 > ALL (SELECT * from t1)
0
select 10.5 > ALL (SELECT * from t1);
10.5 > ALL (SELECT * from t1)
NULL
select 1.5 > ANY (SELECT * from t1);
1.5 > ANY (SELECT * from t1)
NULL
select 10.5 > ANY (SELECT * from t1);
10.5 > ANY (SELECT * from t1)
1
explain extended select (select a+1) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
Warnings:
Note	1276	Field or reference 'a' of SELECT #2 was resolved in SELECT #1
Note	1249	Select 2 was reduced during optimisation
Note	1003	select (test.t1.a + 1) AS `(select a+1)` from test.t1
select (select a+1) from t1;
(select a+1)
2.5
NULL
4.5
drop table t1;
CREATE TABLE t1 (a int(11) NOT NULL default '0', PRIMARY KEY  (a));
CREATE TABLE t2 (a int(11) default '0', INDEX (a));
INSERT INTO t1 VALUES (1),(2),(3),(4);
INSERT INTO t2 VALUES (1),(2),(3);
SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
a	t1.a in (select t2.a from t2)
1	1
2	1
3	1
4	0
explain extended SELECT t1.a, t1.a in (select t2.a from t2) FROM t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	4	Using index
2	DEPENDENT SUBQUERY	t2	index_subquery	a	a	5	func	2	Using index
Warnings:
Note	1003	select test.t1.a AS `a`,<in_optimizer>(test.t1.a,<exists>(<index_lookup>(<cache>(test.t1.a) in t2 on a chicking NULL))) AS `t1.a in (select t2.a from t2)` from test.t1
CREATE TABLE t3 (a int(11) default '0');
INSERT INTO t3 VALUES (1),(2),(3);
SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
a	t1.a in (select t2.a from t2,t3 where t3.a=t2.a)
1	1
2	1
3	1
4	0
explain extended SELECT t1.a, t1.a in (select t2.a from t2,t3 where t3.a=t2.a) FROM t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	4	Using index
2	DEPENDENT SUBQUERY	t2	ref_or_null	a	a	5	func	2	Using where; Using index
2	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
Warnings:
Note	1003	select test.t1.a AS `a`,<in_optimizer>(test.t1.a,<exists>(select 1 AS `Not_used` from test.t2 join test.t3 where ((test.t3.a = test.t2.a) and ((<cache>(test.t1.a) = test.t2.a) or isnull(test.t2.a))) having <is_not_null_test>(test.t2.a))) AS `t1.a in (select t2.a from t2,t3 where t3.a=t2.a)` from test.t1
drop table t1,t2,t3;
create table t1 (a float);
select 10.5 IN (SELECT * from t1 LIMIT 1);
ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
select 10.5 IN (SELECT * from t1 LIMIT 1 UNION SELECT 1.5);
ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
drop table t1;
create table t1 (a int, b int, c varchar(10));
create table t2 (a int);
insert into t1 values (1,2,'a'),(2,3,'b'),(3,4,'c');
insert into t2 values (1),(2),(NULL);
select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a'),(select c from t1 where a=t2.a)  from t2;
a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a')	(select c from t1 where a=t2.a)
1	1	a
2	0	b
NULL	NULL	NULL
select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,3,'b'),(select c from t1 where a=t2.a) from t2;
a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,3,'b')	(select c from t1 where a=t2.a)
1	0	a
2	1	b
NULL	NULL	NULL
select a, (select a,b,c from t1 where t1.a=t2.a) = ROW(a,4,'c'),(select c from t1 where a=t2.a) from t2;
a	(select a,b,c from t1 where t1.a=t2.a) = ROW(a,4,'c')	(select c from t1 where a=t2.a)
1	0	a
2	0	b
NULL	NULL	NULL
drop table t1,t2;
create table t1 (a int, b real, c varchar(10));
insert into t1 values (1, 1, 'a'), (2,2,'b'), (NULL, 2, 'b');
select ROW(1, 1, 'a') IN (select a,b,c from t1);
ROW(1, 1, 'a') IN (select a,b,c from t1)
1
select ROW(1, 2, 'a') IN (select a,b,c from t1);
ROW(1, 2, 'a') IN (select a,b,c from t1)
NULL
select ROW(1, 1, 'a') IN (select b,a,c from t1);
ROW(1, 1, 'a') IN (select b,a,c from t1)
1
select ROW(1, 1, 'a') IN (select a,b,c from t1 where a is not null);
ROW(1, 1, 'a') IN (select a,b,c from t1 where a is not null)
1
select ROW(1, 2, 'a') IN (select a,b,c from t1 where a is not null);
ROW(1, 2, 'a') IN (select a,b,c from t1 where a is not null)
0
select ROW(1, 1, 'a') IN (select b,a,c from t1 where a is not null);
ROW(1, 1, 'a') IN (select b,a,c from t1 where a is not null)
1
select ROW(1, 1, 'a') IN (select a,b,c from t1 where c='b' or c='a');
ROW(1, 1, 'a') IN (select a,b,c from t1 where c='b' or c='a')
1
select ROW(1, 2, 'a') IN (select a,b,c from t1 where c='b' or c='a');
ROW(1, 2, 'a') IN (select a,b,c from t1 where c='b' or c='a')
NULL
select ROW(1, 1, 'a') IN (select b,a,c from t1 where c='b' or c='a');
ROW(1, 1, 'a') IN (select b,a,c from t1 where c='b' or c='a')
1
select ROW(1, 1, 'a') IN (select b,a,c from t1 limit 2);
ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
drop table t1;
create table t1 (a int);
insert into t1 values (1);
do @a:=(SELECT a from t1);
select @a;
@a
1
set @a:=2;
set @a:=(SELECT a from t1);
select @a;
@a
1
drop table t1;
do (SELECT a from t1);
ERROR 42S02: Table 'test.t1' doesn't exist
set @a:=(SELECT a from t1);
ERROR 42S02: Table 'test.t1' doesn't exist
CREATE TABLE t1 (a int, KEY(a));
HANDLER t1 OPEN;
HANDLER t1 READ a=((SELECT 1));
ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT 1))' at line 1
HANDLER t1 CLOSE;
drop table t1;
create table t1 (a int);
create table t2 (b int);
insert into t1 values (1),(2);
insert into t2 values (1);
select a from t1 where a in (select a from t1 where a in (select b from t2));
a
1
drop table t1, t2;
create table t1 (a int, b int);
create table t2 like t1;
insert into t1 values (1,2),(1,3),(1,4),(1,5);
insert into t2 values (1,2),(1,3);
select * from t1 where row(a,b) in (select a,b from t2);
a	b
1	2
1	3
drop table t1, t2;
CREATE TABLE `t1` (`i` int(11) NOT NULL default '0',PRIMARY KEY  (`i`)) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES (1);
UPDATE t1 SET i=i+1 WHERE i=(SELECT MAX(i));
ERROR HY000: Invalid use of group function
drop table t1;
CREATE TABLE t1 (a int(1));
EXPLAIN EXTENDED SELECT (SELECT RAND() FROM t1) FROM t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
2	UNCACHEABLE SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
Warnings:
Note	1003	select sql_no_cache (select sql_no_cache rand() AS `RAND()` from test.t1) AS `(SELECT RAND() FROM t1)` from test.t1
EXPLAIN EXTENDED SELECT (SELECT ENCRYPT('test') FROM t1) FROM t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
2	UNCACHEABLE SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
Warnings:
Note	1003	select sql_no_cache (select sql_no_cache ecrypt(_latin1'test') AS `ENCRYPT('test')` from test.t1) AS `(SELECT ENCRYPT('test') FROM t1)` from test.t1
EXPLAIN EXTENDED SELECT (SELECT BENCHMARK(1,1) FROM t1) FROM t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
2	UNCACHEABLE SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
Warnings:
Note	1003	select sql_no_cache (select sql_no_cache benchmark(1,1) AS `BENCHMARK(1,1)` from test.t1) AS `(SELECT BENCHMARK(1,1) FROM t1)` from test.t1
drop table t1;
CREATE TABLE `t1` (
`mot` varchar(30) character set latin1 NOT NULL default '',
`topic` mediumint(8) unsigned NOT NULL default '0',
`date` date NOT NULL default '0000-00-00',
`pseudo` varchar(35) character set latin1 NOT NULL default '',
PRIMARY KEY  (`mot`,`pseudo`,`date`,`topic`),
KEY `pseudo` (`pseudo`,`date`,`topic`),
KEY `topic` (`topic`)
) ENGINE=MyISAM CHARSET=latin1 ROW_FORMAT=DYNAMIC;
CREATE TABLE `t2` (
`mot` varchar(30) character set latin1 NOT NULL default '',
`topic` mediumint(8) unsigned NOT NULL default '0',
`date` date NOT NULL default '0000-00-00',
`pseudo` varchar(35) character set latin1 NOT NULL default '',
PRIMARY KEY  (`mot`,`pseudo`,`date`,`topic`),
KEY `pseudo` (`pseudo`,`date`,`topic`),
KEY `topic` (`topic`)
) ENGINE=MyISAM CHARSET=latin1 ROW_FORMAT=DYNAMIC;
CREATE TABLE `t3` (
`numeropost` mediumint(8) unsigned NOT NULL auto_increment,
`maxnumrep` int(10) unsigned NOT NULL default '0',
PRIMARY KEY  (`numeropost`),
UNIQUE KEY `maxnumrep` (`maxnumrep`)
) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES ('joce','1','','joce'),('test','2','','test');
Warnings:
Warning	1265	Data truncated for column 'date' at row 1
Warning	1265	Data truncated for column 'date' at row 2
INSERT INTO t2 VALUES ('joce','1','','joce'),('test','2','','test');
Warnings:
Warning	1265	Data truncated for column 'date' at row 1
Warning	1265	Data truncated for column 'date' at row 2
INSERT INTO t3 VALUES (1,1);
SELECT DISTINCT topic FROM t2 WHERE NOT EXISTS(SELECT * FROM t3 WHERE
numeropost=topic);
topic
2
select * from t1;
mot	topic	date	pseudo
joce	1	0000-00-00	joce
test	2	0000-00-00	test
DELETE FROM t1 WHERE topic IN (SELECT DISTINCT topic FROM t2 WHERE NOT
EXISTS(SELECT * FROM t3 WHERE numeropost=topic));
select * from t1;
mot	topic	date	pseudo
joce	1	0000-00-00	joce
drop table t1, t2, t3;
SELECT * FROM (SELECT 1 as a,(SELECT a)) a;
a	(SELECT a)
1	1
CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT 1)) a;
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` bigint(1) NOT NULL default '0',
  `(SELECT 1)` bigint(1) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT a)) a;
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` bigint(1) NOT NULL default '0',
  `(SELECT a)` bigint(1) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
CREATE TABLE t1 SELECT * FROM (SELECT 1 as a,(SELECT a+0)) a;
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` bigint(1) NOT NULL default '0',
  `(SELECT a+0)` bigint(17) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
CREATE TABLE t1 SELECT (SELECT 1 as a UNION SELECT 1+1 limit 1,1) as a;
select * from t1;
a
2
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` bigint(17) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (a int);
insert into t1 values (1), (2), (3);
explain extended select a,(select (select rand() from t1 limit 1)  from t1 limit 1)
from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
2	UNCACHEABLE SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
3	UNCACHEABLE SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
Warnings:
Note	1003	select sql_no_cache test.t1.a AS `a`,(select sql_no_cache (select sql_no_cache rand() AS `rand()` from test.t1 limit 1) AS `(select rand() from t1 limit 1)` from test.t1 limit 1) AS `(select (select rand() from t1 limit 1)  from t1 limit 1)` from test.t1
drop table t1;
select t1.Continent, t2.Name, t2.Population from t1 LEFT JOIN t2 ON t1.Code = t2.Country  where t2.Population IN (select max(t2.Population) AS Population from t2, t1 where t2.Country = t1.Code group by Continent);
ERROR 42S02: Table 'test.t1' doesn't exist
CREATE TABLE t1 (
ID int(11) NOT NULL auto_increment,
name char(35) NOT NULL default '',
t2 char(3) NOT NULL default '',
District char(20) NOT NULL default '',
Population int(11) NOT NULL default '0',
PRIMARY KEY  (ID)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES (130,'Sydney','AUS','New South Wales',3276207);
INSERT INTO t1 VALUES (131,'Melbourne','AUS','Victoria',2865329);
INSERT INTO t1 VALUES (132,'Brisbane','AUS','Queensland',1291117);
CREATE TABLE t2 (
Code char(3) NOT NULL default '',
Name char(52) NOT NULL default '',
Continent enum('Asia','Europe','North America','Africa','Oceania','Antarctica','South America') NOT NULL default 'Asia',
Region char(26) NOT NULL default '',
SurfaceArea float(10,2) NOT NULL default '0.00',
IndepYear smallint(6) default NULL,
Population int(11) NOT NULL default '0',
LifeExpectancy float(3,1) default NULL,
GNP float(10,2) default NULL,
GNPOld float(10,2) default NULL,
LocalName char(45) NOT NULL default '',
GovernmentForm char(45) NOT NULL default '',
HeadOfState char(60) default NULL,
Capital int(11) default NULL,
Code2 char(2) NOT NULL default '',
PRIMARY KEY  (Code)
) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('AUS','Australia','Oceania','Australia and New Zealand',7741220.00,1901,18886000,79.8,351182.00,392911.00,'Australia','Constitutional Monarchy, Federation','Elisabeth II',135,'AU');
INSERT INTO t2 VALUES ('AZE','Azerbaijan','Asia','Middle East',86600.00,1991,7734000,62.9,4127.00,4100.00,'Az�rbaycan','Federal Republic','Heyd�r �liyev',144,'AZ');
select t2.Continent, t1.Name, t1.Population from t2 LEFT JOIN t1 ON t2.Code = t1.t2  where t1.Population IN (select max(t1.Population) AS Population from t1, t2 where t1.t2 = t2.Code group by Continent);
Continent	Name	Population
Oceania	Sydney	3276207
drop table t1, t2;
CREATE TABLE `t1` (
`id` mediumint(8) unsigned NOT NULL auto_increment,
`pseudo` varchar(35) character set latin1 NOT NULL default '',
PRIMARY KEY  (`id`),
UNIQUE KEY `pseudo` (`pseudo`)
) ENGINE=MyISAM PACK_KEYS=1 ROW_FORMAT=DYNAMIC;
INSERT INTO t1 (pseudo) VALUES ('test');
SELECT 0 IN (SELECT 1 FROM t1 a);
0 IN (SELECT 1 FROM t1 a)
0
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
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
Warnings:
Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from test.t1 a)) AS `0 IN (SELECT 1 FROM t1 a)`
INSERT INTO t1 (pseudo) VALUES ('test1');
SELECT 0 IN (SELECT 1 FROM t1 a);
0 IN (SELECT 1 FROM t1 a)
0
EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
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
Warnings:
Note	1003	select <in_optimizer>(0,<exists>(select 1 AS `Not_used` from test.t1 a)) AS `0 IN (SELECT 1 FROM t1 a)`
drop table t1;
CREATE TABLE `t1` (
`i` int(11) NOT NULL default '0',
PRIMARY KEY  (`i`)
) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES (1);
UPDATE t1 SET i=i+(SELECT MAX(i) FROM (SELECT 1) t) WHERE i=(SELECT MAX(i));
ERROR HY000: Invalid use of group function
UPDATE t1 SET i=i+1 WHERE i=(SELECT MAX(i));
ERROR HY000: Invalid use of group function
UPDATE t1 SET t.i=i+(SELECT MAX(i) FROM (SELECT 1) t);
ERROR 42S02: Unknown table 't' in field list
drop table t1;
CREATE TABLE t1 (
id int(11) default NULL
) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES (1),(1),(2),(2),(1),(3);
CREATE TABLE t2 (
id int(11) default NULL,
name varchar(15) default NULL
) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t2 VALUES (4,'vita'), (1,'vita'), (2,'vita'), (1,'vita');
update t1, t2 set t2.name='lenka' where t2.id in (select id from t1);
select * from t2;
id	name
4	vita
1	lenka
2	lenka
1	lenka
drop table t1,t2;
create table t1 (a int, unique index indexa (a));
insert into t1 values (-1), (-4), (-2), (NULL);
select -10 IN (select a from t1 FORCE INDEX (indexa));
-10 IN (select a from t1 FORCE INDEX (indexa))
NULL
drop table t1;
create table t1 (id int not null auto_increment primary key, salary int, key(salary));
insert into t1 (salary) values (100),(1000),(10000),(10),(500),(5000),(50000);
explain extended SELECT id FROM t1 where salary = (SELECT MAX(salary) FROM t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ref	salary	salary	5	const	1	Using where
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
Warnings:
Note	1003	select test.t1.id AS `id` from test.t1 where (test.t1.salary = (select max(test.t1.salary) AS `MAX(salary)` from test.t1))
drop table t1;
CREATE TABLE t1 (
ID int(10) unsigned NOT NULL auto_increment,
SUB_ID int(3) unsigned NOT NULL default '0',
REF_ID int(10) unsigned default NULL,
REF_SUB int(3) unsigned default '0',
PRIMARY KEY (ID,SUB_ID),
UNIQUE KEY t1_PK (ID,SUB_ID),
KEY t1_FK (REF_ID,REF_SUB),
KEY t1_REFID (REF_ID)
) ENGINE=MyISAM CHARSET=cp1251;
INSERT INTO t1 VALUES (1,0,NULL,NULL),(2,0,NULL,NULL);
SELECT DISTINCT REF_ID FROM t1 WHERE ID= (SELECT DISTINCT REF_ID FROM t1 WHERE ID=2);
REF_ID
DROP TABLE t1;
create table t1 (a int, b int);
create table t2 (a int, b int);
insert into t1 values (1,0), (2,0), (3,0);
insert into t2 values (1,1), (2,1), (3,1), (2,2);
update ignore t1 set b=(select b from t2 where t1.a=t2.a);
Warnings:
Error	1242	Subquery returns more than 1 row
select * from t1;
a	b
1	1
2	NULL
3	1
drop table t1, t2;
create table t1(City VARCHAR(30),Location geometry);
insert into t1 values("Paris",GeomFromText('POINT(2.33 48.87)'));
select City from t1 where (select intersects(GeomFromText(AsText(Location)),GeomFromText('Polygon((2 50, 2.5 50, 2.5 47, 2 47, 2 50))'))=0);
City
drop table t1;
CREATE TABLE `t1` (
`id` mediumint(8) unsigned NOT NULL auto_increment,
`pseudo` varchar(35) NOT NULL default '',
`email` varchar(60) NOT NULL default '',
PRIMARY KEY  (`id`),
UNIQUE KEY `email` (`email`),
UNIQUE KEY `pseudo` (`pseudo`)
) ENGINE=MyISAM CHARSET=latin1 PACK_KEYS=1 ROW_FORMAT=DYNAMIC;
INSERT INTO t1 (id,pseudo,email) VALUES (1,'test','test'),(2,'test1','test1');
SELECT pseudo as a, pseudo as b FROM t1 GROUP BY (SELECT a) ORDER BY (SELECT id*1);
a	b
test	test
test1	test1
drop table if exists t1;
(SELECT 1 as a) UNION (SELECT 1) ORDER BY (SELECT a+0);
a
1
create table t1 (a int not null, b int, primary key (a));
create table t2 (a int not null, primary key (a));
create table t3 (a int not null, b int, primary key (a));
insert into t1 values (1,10), (2,20), (3,30),  (4,40);
insert into t2 values (2), (3), (4), (5);
insert into t3 values (10,3), (20,4), (30,5);
select * from t2 where t2.a in (select a from t1);
a
2
3
4
explain extended select * from t2 where t2.a in (select a from t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(<primary_index_lookup>(<cache>(test.t2.a) in t1 on PRIMARY)))
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
a
2
4
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index; Using where
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(<primary_index_lookup>(<cache>(test.t2.a) in t1 on PRIMARY where (test.t1.b <> 30))))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
a
2
3
explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	func	1	Using where
2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	Using where; Using index
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(select 1 AS `Not_used` from test.t1 join test.t3 where ((test.t1.b = test.t3.a) and (<cache>(test.t2.a) = test.t1.a))))
drop table t1, t2, t3;
create table t1 (a int, b int, index a (a,b));
create table t2 (a int, index a (a));
create table t3 (a int, b int, index a (a));
insert into t1 values (1,10), (2,20), (3,30), (4,40);
insert into t2 values (2), (3), (4), (5);
insert into t3 values (10,3), (20,4), (30,5);
select * from t2 where t2.a in (select a from t1);
a
2
3
4
explain extended select * from t2 where t2.a in (select a from t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	Using index
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(<index_lookup>(<cache>(test.t2.a) in t1 on a)))
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
a
2
4
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	Using index; Using where
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(<index_lookup>(<cache>(test.t2.a) in t1 on a where (test.t1.b <> 30))))
select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
a
2
3
explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	ref	a	a	5	func	1001	Using where; Using index
2	DEPENDENT SUBQUERY	t3	index	a	a	5	NULL	3	Using where; Using index
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(select 1 AS `Not_used` from test.t1 join test.t3 where ((test.t1.b = test.t3.a) and (<cache>(test.t2.a) = test.t1.a))))
insert into t1 values (3,31);
select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
a
2
3
4
select * from t2 where t2.a in (select a from t1 where t1.b <> 30 and t1.b <> 31);
a
2
4
explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1001	Using index; Using where
Warnings:
Note	1003	select test.t2.a AS `a` from test.t2 where <in_optimizer>(test.t2.a,<exists>(<index_lookup>(<cache>(test.t2.a) in t1 on a where (test.t1.b <> 30))))
drop table t1, t2, t3;
create table t1 (a int, b int);
create table t2 (a int, b int);
create table t3 (a int, b int);
insert into t1 values (0,100),(1,2), (1,3), (2,2), (2,7), (2,-1), (3,10);
insert into t2 values (0,0), (1,1), (2,1), (3,1), (4,1);
insert into t3 values (3,3), (2,2), (1,1);
select a,(select count(distinct t1.b) as sum from t1,t2 where t1.a=t2.a and t2.b > 0 and t1.a <= t3.b group by t1.a order by sum limit 1) from t3;
a	(select count(distinct t1.b) as sum from t1,t2 where t1.a=t2.a and t2.b > 0 and t1.a <= t3.b group by t1.a order by sum limit 1)
3	1
2	2
1	2
drop table t1,t2,t3;
create table t1 (s1 int);
create table t2 (s1 int);
insert into t1 values (1);
insert into t2 values (1);
select * from t1 where exists (select s1 from t2 having max(t2.s1)=t1.s1);
s1
1
drop table t1,t2;
create table t1 (s1 int);
create table t2 (s1 int);
insert into t1 values (1);
insert into t2 values (1);
update t1 set  s1 = s1 + 1 where 1 = (select x.s1 as A from t2 WHERE t2.s1 > t1.s1 order by A);
ERROR 42S22: Unknown column 'x.s1' in 'field list'
DROP TABLE t1, t2;
CREATE TABLE t1 (s1 CHAR(5) COLLATE latin1_german1_ci,
s2 CHAR(5) COLLATE latin1_swedish_ci);
INSERT INTO t1 VALUES ('z','?');
select * from t1 where s1 > (select max(s2) from t1);
ERROR HY000: Illegal mix of collations (latin1_german1_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '>'
select * from t1 where s1 > any (select max(s2) from t1);
ERROR HY000: Illegal mix of collations (latin1_german1_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '>'
drop table t1;
create table t1(toid int,rd int);
create table t2(userid int,pmnew int,pmtotal int);
insert into t2 values(1,0,0),(2,0,0);
insert into t1 values(1,0),(1,0),(1,0),(1,12),(1,15),(1,123),(1,12312),(1,12312),(1,123),(2,0),(2,0),(2,1),(2,2);
select userid,pmtotal,pmnew, (select count(rd) from t1 where toid=t2.userid) calc_total, (select count(rd) from t1 where rd=0 and toid=t2.userid) calc_new from t2 where userid in (select distinct toid from t1);
userid	pmtotal	pmnew	calc_total	calc_new
1	0	0	9	3
2	0	0	4	2
drop table t1, t2;
create table t1 (s1 char(5));
select (select 'a','b' from t1 union select 'a','b' from t1) from t1;
ERROR 21000: Operand should contain 1 column(s)
insert into t1 values ('tttt');
select * from t1 where ('a','b')=(select 'a','b' from t1 union select 'a','b' from t1);
s1
tttt
explain extended (select * from t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	
Warnings:
Note	1003	(select test.t1.s1 AS `s1` from test.t1)
(select * from t1);
s1
tttt
drop table t1;
create table t1 (s1 char(5), index s1(s1));
create table t2 (s1 char(5), index s1(s1));
insert into t1 values ('a1'),('a2'),('a3');
insert into t2 values ('a1'),('a2');
select s1, s1 NOT IN (SELECT s1 FROM t2) from t1;
s1	s1 NOT IN (SELECT s1 FROM t2)
a1	0
a2	0
a3	1
select s1, s1 = ANY (SELECT s1 FROM t2) from t1;
s1	s1 = ANY (SELECT s1 FROM t2)
a1	1
a2	1
a3	0
select s1, s1 <> ALL (SELECT s1 FROM t2) from t1;
s1	s1 <> ALL (SELECT s1 FROM t2)
a1	0
a2	0
a3	1
select s1, s1 NOT IN (SELECT s1 FROM t2 WHERE s1 < 'a2') from t1;
s1	s1 NOT IN (SELECT s1 FROM t2 WHERE s1 < 'a2')
a1	0
a2	1
a3	1
explain extended select s1, s1 NOT IN (SELECT s1 FROM t2) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	s1	6	NULL	3	Using index
2	DEPENDENT SUBQUERY	t2	index_subquery	s1	s1	6	func	2	Using index
Warnings:
Note	1003	select test.t1.s1 AS `s1`,not(<in_optimizer>(test.t1.s1,<exists>(<index_lookup>(<cache>(test.t1.s1) in t2 on s1 chicking NULL)))) AS `s1 NOT IN (SELECT s1 FROM t2)` from test.t1
explain extended select s1, s1 = ANY (SELECT s1 FROM t2) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	s1	6	NULL	3	Using index
2	DEPENDENT SUBQUERY	t2	index_subquery	s1	s1	6	func	2	Using index
Warnings:
Note	1003	select test.t1.s1 AS `s1`,<in_optimizer>(test.t1.s1,<exists>(<index_lookup>(<cache>(test.t1.s1) in t2 on s1 chicking NULL))) AS `s1 = ANY (SELECT s1 FROM t2)` from test.t1
explain extended select s1, s1 <> ALL (SELECT s1 FROM t2) from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	s1	6	NULL	3	Using index
2	DEPENDENT SUBQUERY	t2	index_subquery	s1	s1	6	func	2	Using index
Warnings:
Note	1003	select test.t1.s1 AS `s1`,not(<in_optimizer>(test.t1.s1,<exists>(<index_lookup>(<cache>(test.t1.s1) in t2 on s1 chicking NULL)))) AS `s1 <> ALL (SELECT s1 FROM t2)` from test.t1
explain extended select s1, s1 NOT IN (SELECT s1 FROM t2 WHERE s1 < 'a2') from t1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	index	NULL	s1	6	NULL	3	Using index
2	DEPENDENT SUBQUERY	t2	index_subquery	s1	s1	6	func	1	Using index; Using where
Warnings:
Note	1003	select test.t1.s1 AS `s1`,not(<in_optimizer>(test.t1.s1,<exists>(<index_lookup>(<cache>(test.t1.s1) in t2 on s1 chicking NULL where (test.t2.s1 < _latin1'a2'))))) AS `s1 NOT IN (SELECT s1 FROM t2 WHERE s1 < 'a2')` from test.t1
drop table t1,t2;
create table t2 (a int, b int);
create table t3 (a int);
insert into t3 values (6),(7),(3);
select * from t3 where a >= all (select b from t2);
a
6
7
3
explain extended select * from t3 where a >= all (select b from t2);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
2	SUBQUERY	t2	system	NULL	NULL	NULL	NULL	0	const row not found
Warnings:
Note	1003	select test.t3.a AS `a` from test.t3 where <not>((test.t3.a < (select max(test.t2.b) from test.t2)))
insert into t2 values (2,2), (2,1), (3,3), (3,1);
select * from t3 where a > all (select max(b) from t2 group by a);
a
6
7
explain extended select * from t3 where a > all (select max(b) from t2 group by a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
Warnings:
Note	1003	select test.t3.a AS `a` from test.t3 where <not>((test.t3.a <= <max>(select max(test.t2.b) AS `max(b)` from test.t2 group by test.t2.a)))
drop table t2, t3;
CREATE TABLE `t1` ( `id` mediumint(9) NOT NULL auto_increment, `taskid` bigint(20) NOT NULL default '0', `dbid` int(11) NOT NULL default '0', `create_date` datetime NOT NULL default '0000-00-00 00:00:00', `last_update` datetime NOT NULL default '0000-00-00 00:00:00', PRIMARY KEY  (`id`)) ENGINE=MyISAM CHARSET=latin1 AUTO_INCREMENT=3 ;
INSERT INTO `t1` (`id`, `taskid`, `dbid`, `create_date`,`last_update`) VALUES (1, 1, 15, '2003-09-29 10:31:36', '2003-09-29 10:31:36'), (2, 1, 21, now(), now());
CREATE TABLE `t2` (`db_id` int(11) NOT NULL auto_increment,`name` varchar(200) NOT NULL default '',`primary_uid` smallint(6) NOT NULL default '0',`secondary_uid` smallint(6) NOT NULL default '0',PRIMARY KEY  (`db_id`),UNIQUE KEY `name_2` (`name`),FULLTEXT KEY `name` (`name`)) ENGINE=MyISAM CHARSET=latin1 AUTO_INCREMENT=2147483647;
INSERT INTO `t2` (`db_id`, `name`, `primary_uid`, `secondary_uid`) VALUES (18, 'Not Set 1', 0, 0),(19, 'Valid', 1, 2),(20, 'Valid 2', 1, 2),(21, 'Should Not Return', 1, 2),(26, 'Not Set 2', 0, 0),(-1, 'ALL DB\'S', 0, 0);
CREATE TABLE `t3` (`taskgenid` mediumint(9) NOT NULL auto_increment,`dbid` int(11) NOT NULL default '0',`taskid` int(11) NOT NULL default '0',`mon` tinyint(4) NOT NULL default '1',`tues` tinyint(4) NOT NULL default '1',`wed` tinyint(4) NOT NULL default '1',`thur` tinyint(4) NOT NULL default '1',`fri` tinyint(4) NOT NULL default '1',`sat` tinyint(4) NOT NULL default '0',`sun` tinyint(4) NOT NULL default '0',`how_often` smallint(6) NOT NULL default '1',`userid` smallint(6) NOT NULL default '0',`active` tinyint(4) NOT NULL default '1',PRIMARY KEY  (`taskgenid`)) ENGINE=MyISAM CHARSET=latin1 AUTO_INCREMENT=2 ;
INSERT INTO `t3` (`taskgenid`, `dbid`, `taskid`, `mon`, `tues`,`wed`, `thur`, `fri`, `sat`, `sun`, `how_often`, `userid`, `active`) VALUES (1,-1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 1);
CREATE TABLE `t4` (`task_id` smallint(6) NOT NULL default '0',`description` varchar(200) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
INSERT INTO `t4` (`task_id`, `description`) VALUES (1, 'Daily Check List'),(2, 'Weekly Status');
select  dbid, name, (date_format(now() , '%Y-%m-%d') - INTERVAL how_often DAY) >= ifnull((SELECT date_format(max(create_date),'%Y-%m-%d') FROM t1 WHERE dbid = b.db_id AND taskid = a.taskgenid), '1950-01-01') from t3 a, t2 b, t4  WHERE dbid = - 1 AND primary_uid = '1' AND t4.task_id = taskid;
dbid	name	(date_format(now() , '%Y-%m-%d') - INTERVAL how_often DAY) >= ifnull((SELECT date_format(max(create_date),'%Y-%m-%d') FROM t1 WHERE dbid = b.db_id AND taskid = a.taskgenid), '1950-01-01')
-1	Valid	1
-1	Valid 2	1
-1	Should Not Return	0
SELECT dbid, name FROM t3 a, t2 b, t4 WHERE dbid = - 1 AND primary_uid = '1' AND ((date_format(now() , '%Y-%m-%d') - INTERVAL how_often DAY) >= ifnull((SELECT date_format(max(create_date),'%Y-%m-%d') FROM t1 WHERE dbid = b.db_id AND taskid = a.taskgenid), '1950-01-01')) AND t4.task_id = taskid;
dbid	name
-1	Valid
-1	Valid 2
drop table t1,t2,t3,t4;
CREATE TABLE t1 (id int(11) default NULL) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES (1),(5);
CREATE TABLE t2 (id int(11) default NULL) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t2 VALUES (2),(6);
select * from t1 where (1,2,6) in (select * from t2);
ERROR 21000: Operand should contain 3 column(s)
DROP TABLE t1,t2;
create table t1 (s1 int);
insert into t1 values (1);
insert into t1 values (2);
set sort_buffer_size = (select s1 from t1);
ERROR 21000: Subquery returns more than 1 row
do (select * from t1);
drop table t1;
create table t1 (s1 char);
insert into t1 values ('e');
select * from t1 where 'f' > any (select s1 from t1);
s1
e
select * from t1 where 'f' > any (select s1 from t1 union select s1 from t1);
s1
e
explain extended select * from t1 where 'f' > any (select s1 from t1 union select s1 from t1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	
2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	
3	UNION	t1	system	NULL	NULL	NULL	NULL	1	
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	select test.t1.s1 AS `s1` from test.t1
drop table t1;
CREATE TABLE t1 (number char(11) NOT NULL default '') ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t1 VALUES ('69294728265'),('18621828126'),('89356874041'),('95895001874');
CREATE TABLE t2 (code char(5) NOT NULL default '',UNIQUE KEY code (code)) ENGINE=MyISAM CHARSET=latin1;
INSERT INTO t2 VALUES ('1'),('1226'),('1245'),('1862'),('18623'),('1874'),('1967'),('6');
select c.number as phone,(select p.code from t2 p where c.number like concat(p.code, '%') order by length(p.code) desc limit 1) as code from t1 c;
phone	code
69294728265	6
18621828126	1862
89356874041	NULL
95895001874	NULL
drop table t1, t2;
create table t1 (s1 int);
create table t2 (s1 int);
select * from t1 where (select count(*) from t2 where t1.s2) = 1;
ERROR 42S22: Unknown column 't1.s2' in 'where clause'
select * from t1 where (select count(*) from t2 group by t1.s2) = 1;
ERROR 42S22: Unknown column 't1.s2' in 'group statement'
select count(*) from t2 group by t1.s2;
ERROR 42S02: Unknown table 't1' in group statement
drop table t1, t2;
CREATE TABLE t1(COLA FLOAT NOT NULL,COLB FLOAT NOT NULL,COLC VARCHAR(20) DEFAULT NULL,PRIMARY KEY (COLA, COLB));
CREATE TABLE t2(COLA FLOAT NOT NULL,COLB FLOAT NOT NULL,COLC CHAR(1) NOT NULL,PRIMARY KEY (COLA));
INSERT INTO t1 VALUES (1,1,'1A3240'), (1,2,'4W2365');
INSERT INTO t2 VALUES (100, 200, 'C');
SELECT DISTINCT COLC FROM t1 WHERE COLA = (SELECT COLA FROM t2 WHERE COLB = 200 AND COLC ='C' LIMIT 1);
COLC
DROP TABLE t1, t2;
CREATE TABLE t1 (a int(1));
INSERT INTO t1 VALUES (1),(1),(1),(1),(1),(2),(3),(4),(5);
SELECT DISTINCT (SELECT a) FROM t1 LIMIT 100;
(SELECT a)
1
2
3
4
5
DROP TABLE t1;
create table t1 (a int, b decimal(13, 3));
insert into t1 values (1, 0.123);
select a, (select max(b) from t1) into outfile "subselect.out.file.1" from t1;
delete from t1;
load data infile "subselect.out.file.1" into table t1;
select * from t1;
a	b
1	0.123
drop table t1;
CREATE TABLE `t1` (
`id` int(11) NOT NULL auto_increment,
`id_cns` tinyint(3) unsigned NOT NULL default '0',
`tipo` enum('','UNO','DUE') NOT NULL default '',
`anno_dep` smallint(4) unsigned zerofill NOT NULL default '0000',
`particolare` mediumint(8) unsigned NOT NULL default '0',
`generale` mediumint(8) unsigned NOT NULL default '0',
`bis` tinyint(3) unsigned NOT NULL default '0',
PRIMARY KEY  (`id`),
UNIQUE KEY `idx_cns_gen_anno` (`anno_dep`,`id_cns`,`generale`,`particolare`),
UNIQUE KEY `idx_cns_par_anno` (`id_cns`,`anno_dep`,`tipo`,`particolare`,`bis`)
);
INSERT INTO `t1` VALUES (1,16,'UNO',1987,2048,9681,0),(2,50,'UNO',1987,1536,13987,0),(3,16,'UNO',1987,2432,14594,0),(4,16,'UNO',1987,1792,13422,0),(5,16,'UNO',1987,1025,10240,0),(6,16,'UNO',1987,1026,7089,0);
CREATE TABLE `t2` (
`id` tinyint(3) unsigned NOT NULL auto_increment,
`max_anno_dep` smallint(6) unsigned NOT NULL default '0',
PRIMARY KEY  (`id`)
);
INSERT INTO `t2` VALUES (16,1987),(50,1990),(51,1990);
SELECT cns.id, cns.max_anno_dep, cns.max_anno_dep = (SELECT s.anno_dep FROM t1 AS s WHERE s.id_cns = cns.id ORDER BY s.anno_dep DESC LIMIT 1) AS PIPPO FROM t2 AS cns;
id	max_anno_dep	PIPPO
16	1987	1
50	1990	0
51	1990	NULL
DROP TABLE t1, t2;
create table t1 (a int);
insert into t1 values (1), (2), (3);
SET SQL_SELECT_LIMIT=1;
select sum(a) from (select * from t1) as a;
sum(a)
6
select 2 in (select * from t1);
2 in (select * from t1)
1
SET SQL_SELECT_LIMIT=default;
drop table t1;
CREATE TABLE t1 (a int, b int, INDEX (a));
INSERT INTO t1 VALUES (1, 1), (1, 2), (1, 3);
SELECT * FROM t1 WHERE a = (SELECT MAX(a) FROM t1 WHERE a = 1) ORDER BY b;
a	b
1	1
1	2
1	3
DROP TABLE t1;
create table t1(val varchar(10));
insert into t1 values ('aaa'), ('bbb'),('eee'),('mmm'),('ppp');
select count(*) from t1 as w1 where w1.val in (select w2.val from t1 as w2 where w2.val like 'm%') and w1.val in (select w3.val from t1 as w3 where w3.val like 'e%');
count(*)
0
drop table t1;
create table t1 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t1 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text11'), (12, 'text12');
select * from t1 where id not in (select id from t1 where id < 8);
id	text
8	text8
9	text9
10	text10
11	text11
12	text12
select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
id	text
8	text8
9	text9
10	text10
11	text11
12	text12
explain extended select * from t1 where id not in (select id from t1 where id < 8);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	12	Using where
2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index; Using where
Warnings:
Note	1003	select test.t1.id AS `id`,test.t1.text AS `text` from test.t1 where not(<in_optimizer>(test.t1.id,<exists>(<primary_index_lookup>(<cache>(test.t1.id) in t1 on PRIMARY where (test.t1.id < 8)))))
explain extended select * from t1 as tt where not exists (select id from t1 where id < 8 and (id = tt.id or id is null) having id is not null);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	tt	ALL	NULL	NULL	NULL	NULL	12	Using where
2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	test.tt.id	7	Using where; Using index
Warnings:
Note	1276	Field or reference 'tt.id' of SELECT #2 was resolved in SELECT #1
Note	1003	select test.tt.id AS `id`,test.tt.text AS `text` from test.t1 tt where not(exists(select test.t1.id AS `id` from test.t1 where ((test.t1.id < 8) and ((test.t1.id = test.tt.id) or isnull(test.t1.id))) having (test.t1.id is not null)))
insert into t1 (id, text) values (1000, 'text1000'), (1001, 'text1001');
create table t2 (id int not null, text varchar(20) not null default '', primary key (id));
insert into t2 (id, text) values (1, 'text1'), (2, 'text2'), (3, 'text3'), (4, 'text4'), (5, 'text5'), (6, 'text6'), (7, 'text7'), (8, 'text8'), (9, 'text9'), (10, 'text10'), (11, 'text1'), (12, 'text2'), (13, 'text3'), (14, 'text4'), (15, 'text5'), (16, 'text6'), (17, 'text7'), (18, 'text8'), (19, 'text9'), (20, 'text10'),(21, 'text1'), (22, 'text2'), (23, 'text3'), (24, 'text4'), (25, 'text5'), (26, 'text6'), (27, 'text7'), (28, 'text8'), (29, 'text9'), (30, 'text10'), (31, 'text1'), (32, 'text2'), (33, 'text3'), (34, 'text4'), (35, 'text5'), (36, 'text6'), (37, 'text7'), (38, 'text8'), (39, 'text9'), (40, 'text10'), (41, 'text1'), (42, 'text2'), (43, 'text3'), (44, 'text4'), (45, 'text5'), (46, 'text6'), (47, 'text7'), (48, 'text8'), (49, 'text9'), (50, 'text10');
select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
id	text	id	text	id	text
1	text1	1	text1	1	text1
2	text2	2	text2	2	text2
3	text3	3	text3	3	text3
4	text4	4	text4	4	text4
5	text5	5	text5	5	text5
6	text6	6	text6	6	text6
7	text7	7	text7	7	text7
8	text8	8	text8	8	text8
9	text9	9	text9	9	text9
10	text10	10	text10	10	text10
11	text11	11	text1	11	text11
12	text12	12	text2	12	text12
1000	text1000	NULL	NULL	1000	text1000
1001	text1001	NULL	NULL	1000	text1000
explain extended select * from t1 a left join t2 b on (a.id=b.id or b.id is null) join t1 c on (if(isnull(b.id), 1000, b.id)=c.id);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	a	ALL	NULL	NULL	NULL	NULL	14	
1	SIMPLE	b	eq_ref	PRIMARY	PRIMARY	4	test.a.id	2	
1	SIMPLE	c	eq_ref	PRIMARY	PRIMARY	4	func	1	Using where
Warnings:
Note	1003	select test.a.id AS `id`,test.a.text AS `text`,test.b.id AS `id`,test.b.text AS `text`,test.c.id AS `id`,test.c.text AS `text` from test.t1 a left join test.t2 b on(((test.a.id = test.b.id) or isnull(test.b.id))) join test.t1 c where (if(isnull(test.b.id),1000,test.b.id) = test.c.id)
drop table t1,t2;
create table t1 (a int);
insert into t1 values (1);
explain select benchmark(1000, (select a from t1 where a=sha(rand())));
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	UNCACHEABLE SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	
drop table t1;
create table t1(id int);
create table t2(id int);
create table t3(flag int);
select (select * from t3 where id not null) from t1, t2;
ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near 'null) from t1, t2' at line 1
drop table t1,t2,t3;
CREATE TABLE t1 (id INT);
CREATE TABLE t2 (id INT);
INSERT INTO t1 VALUES (1), (2);
INSERT INTO t2 VALUES (1);
SELECT t1.id, ( SELECT COUNT(t.id) FROM t2 AS t WHERE t.id = t1.id ) AS c FROM t1 LEFT JOIN t2 USING (id);
id	c
1	1
2	0
SELECT t1.id, ( SELECT COUNT(t.id) FROM t2 AS t WHERE t.id = t1.id ) AS c FROM t1 LEFT JOIN t2 USING (id) ORDER BY t1.id;
id	c
1	1
2	0
DROP TABLE t1,t2;
CREATE TABLE t1 ( a int, b int );
INSERT INTO t1 VALUES (1,1),(2,2),(3,3);
SELECT a FROM t1 WHERE a > ANY ( SELECT a FROM t1 WHERE b = 2 );
a
3
SELECT a FROM t1 WHERE a < ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
SELECT a FROM t1 WHERE a = ANY ( SELECT a FROM t1 WHERE b = 2 );
a
2
SELECT a FROM t1 WHERE a >= ANY ( SELECT a FROM t1 WHERE b = 2 );
a
2
3
SELECT a FROM t1 WHERE a <= ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
2
SELECT a FROM t1 WHERE a <> ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
3
SELECT a FROM t1 WHERE a > ALL ( SELECT a FROM t1 WHERE b = 2 );
a
3
SELECT a FROM t1 WHERE a < ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
SELECT a FROM t1 WHERE a = ALL ( SELECT a FROM t1 WHERE b = 2 );
a
2
SELECT a FROM t1 WHERE a >= ALL ( SELECT a FROM t1 WHERE b = 2 );
a
2
3
SELECT a FROM t1 WHERE a <= ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
2
SELECT a FROM t1 WHERE a <> ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
3
ALTER TABLE t1 ADD INDEX (a);
SELECT a FROM t1 WHERE a > ANY ( SELECT a FROM t1 WHERE b = 2 );
a
3
SELECT a FROM t1 WHERE a < ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
SELECT a FROM t1 WHERE a = ANY ( SELECT a FROM t1 WHERE b = 2 );
a
2
SELECT a FROM t1 WHERE a >= ANY ( SELECT a FROM t1 WHERE b = 2 );
a
2
3
SELECT a FROM t1 WHERE a <= ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
2
SELECT a FROM t1 WHERE a <> ANY ( SELECT a FROM t1 WHERE b = 2 );
a
1
3
SELECT a FROM t1 WHERE a > ALL ( SELECT a FROM t1 WHERE b = 2 );
a
3
SELECT a FROM t1 WHERE a < ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
SELECT a FROM t1 WHERE a = ALL ( SELECT a FROM t1 WHERE b = 2 );
a
2
SELECT a FROM t1 WHERE a >= ALL ( SELECT a FROM t1 WHERE b = 2 );
a
2
3
SELECT a FROM t1 WHERE a <= ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
2
SELECT a FROM t1 WHERE a <> ALL ( SELECT a FROM t1 WHERE b = 2 );
a
1
3
DROP TABLE t1;
create table t1 (a int, b int);
insert into t1 values (1,2),(3,4);
select * from t1 up where exists (select * from t1 where t1.a=up.a);
a	b
1	2
3	4
explain extended select * from t1 up where exists (select * from t1 where t1.a=up.a);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	up	ALL	NULL	NULL	NULL	NULL	2	Using where
2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
Warnings:
Note	1276	Field or reference 'up.a' of SELECT #2 was resolved in SELECT #1
Note	1003	select test.up.a AS `a`,test.up.b AS `b` from test.t1 up where exists(select 1 AS `Not_used` from test.t1 where (test.t1.a = test.up.a))
drop table t1;
CREATE TABLE t1 (t1_a int);
INSERT INTO t1 VALUES (1);
CREATE TABLE t2 (t2_a int, t2_b int, PRIMARY KEY (t2_a, t2_b));
INSERT INTO t2 VALUES (1, 1), (1, 2);
SELECT * FROM t1, t2 table2 WHERE t1_a = 1 AND table2.t2_a = 1
HAVING table2.t2_b = (SELECT MAX(t2_b) FROM t2 WHERE t2_a = table2.t2_a);
t1_a	t2_a	t2_b
1	1	2
DROP TABLE t1, t2;