drop table if exists t1,t2,t3,t4,t5,t6;
CREATE TABLE t1 (a int not null, b char (10) not null);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
CREATE TABLE t2 (a int not null, b char (10) not null);
insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
select a,b from t1 union distinct select a,b from t2;
a	b
1	a
2	b
3	c
4	d
5	f
6	e
select a,b from t1 union all select a,b from t2;
a	b
1	a
2	b
3	c
3	c
3	c
4	d
5	f
6	e
select a,b from t1 union all select a,b from t2 order by b;
a	b
1	a
2	b
3	c
3	c
3	c
4	d
6	e
5	f
select a,b from t1 union all select a,b from t2 union select 7,'g';
a	b
1	a
2	b
3	c
4	d
5	f
6	e
7	g
select 0,'#' union select a,b from t1 union all select a,b from t2 union select 7,'gg';
0	#
0	#
1	a
2	b
3	c
4	d
5	f
6	e
7	gg
select a,b from t1 union select a,b from t1;
a	b
1	a
2	b
3	c
select 't1',b,count(*) from t1 group by b UNION select 't2',b,count(*) from t2 group by b;
t1	b	count(*)
t1	a	1
t1	b	1
t1	c	2
t2	c	1
t2	d	1
t2	e	1
t2	f	1
(select a,b from t1 limit 2)  union all (select a,b from t2 order by a) limit 4;
a	b
1	a
2	b
3	c
4	d
(select a,b from t1 limit 2)  union all (select a,b from t2 order by a limit 1);
a	b
1	a
2	b
3	c
(select a,b from t1 limit 2)  union all (select a,b from t2 order by a limit 1) order by b desc;
a	b
3	c
2	b
1	a
(select a,b from t1 limit 2)  union all (select a,b from t2 order by a limit 1) order by t1.b;
ERROR 42000: Table 't1' from one of the SELECTs cannot be used in global ORDER clause
explain extended (select a,b from t1 limit 2)  union all (select a,b from t2 order by a limit 1) order by b desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
2	UNION	t2	ALL	NULL	NULL	NULL	NULL	4	Using filesort
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	Using filesort
Warnings:
Note	1003	(select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` limit 2) union all (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` order by `test`.`t2`.`a` limit 1) order by `b` desc
(select sql_calc_found_rows  a,b from t1 limit 2)  union all (select a,b from t2 order by a) limit 2;
a	b
1	a
2	b
select found_rows();
found_rows()
6
select sql_calc_found_rows  a,b from t1  union all select a,b from t2 limit 2;
a	b
1	a
2	b
select found_rows();
found_rows()
8
explain select a,b from t1 union all select a,b from t2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
2	UNION	t2	ALL	NULL	NULL	NULL	NULL	4	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
explain select xx from t1 union select 1;
ERROR 42S22: Unknown column 'xx' in 'field list'
explain select a,b from t1 union select 1;
ERROR 21000: The used SELECT statements have a different number of columns
explain select 1 union select a,b from t1 union select 1;
ERROR 21000: The used SELECT statements have a different number of columns
explain select a,b from t1 union select 1 limit 0;
ERROR 21000: The used SELECT statements have a different number of columns
select a,b from t1 into outfile 'skr' union select a,b from t2;
ERROR HY000: Incorrect usage of UNION and INTO
select a,b from t1 order by a union select a,b from t2;
ERROR HY000: Incorrect usage of UNION and ORDER BY
insert into t3 select a from t1 order by a union select a from t2;
ERROR HY000: Incorrect usage of UNION and ORDER BY
create table t3 select a,b from t1 union select a from t2;
ERROR 21000: The used SELECT statements have a different number of columns
select a,b from t1 union select a from t2;
ERROR 21000: The used SELECT statements have a different number of columns
select * from t1 union select a from t2;
ERROR 21000: The used SELECT statements have a different number of columns
select a from t1 union select * from t2;
ERROR 21000: The used SELECT statements have a different number of columns
select * from t1 union select SQL_BUFFER_RESULT * from t2;
ERROR 42000: Incorrect usage/placement of 'SQL_BUFFER_RESULT'
create table t3 select a,b from t1 union all select a,b from t2;
insert into t3 select a,b from t1 union all select a,b from t2;
replace into t3 select a,b as c from t1 union all select a,b from t2;
drop table t1,t2,t3;
select * union select 1;
ERROR HY000: No tables used
select 1 as a,(select a union select a);
a	(select a union select a)
1	1
(select 1) union (select 2) order by 0;
ERROR 42S22: Unknown column '0' in 'order clause'
SELECT @a:=1 UNION SELECT @a:=@a+1;
@a:=1
1
2
(SELECT 1) UNION (SELECT 2) ORDER BY (SELECT a);
ERROR 42S22: Unknown column 'a' in 'field list'
(SELECT 1,3) UNION (SELECT 2,1) ORDER BY (SELECT 2);
1	3
1	3
2	1
CREATE TABLE t1 (
`pseudo` char(35) NOT NULL default '',
`pseudo1` char(35) NOT NULL default '',
`same` tinyint(1) unsigned NOT NULL default '1',
PRIMARY KEY  (`pseudo1`),
KEY `pseudo` (`pseudo`)
) ENGINE=MyISAM;
INSERT INTO t1 (pseudo,pseudo1,same) VALUES ('joce', 'testtt', 1),('joce', 'tsestset', 1),('dekad', 'joce', 1);
SELECT pseudo FROM t1 WHERE pseudo1='joce' UNION SELECT pseudo FROM t1 WHERE pseudo='joce';
pseudo
dekad
joce
SELECT pseudo1 FROM t1 WHERE pseudo1='joce' UNION SELECT pseudo1 FROM t1 WHERE pseudo='joce';
pseudo1
joce
testtt
tsestset
SELECT * FROM t1 WHERE pseudo1='joce' UNION SELECT * FROM t1 WHERE pseudo='joce' order by pseudo desc,pseudo1 desc;
pseudo	pseudo1	same
joce	tsestset	1
joce	testtt	1
dekad	joce	1
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION SELECT pseudo FROM t1 WHERE pseudo1='joce';
pseudo1
testtt
tsestset
dekad
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION ALL SELECT pseudo FROM t1 WHERE pseudo1='joce';
pseudo1
testtt
tsestset
dekad
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION SELECT 1;
pseudo1
testtt
tsestset
1
drop table t1;
create table t1 (a int);
create table t2 (a int);
insert into t1 values (1),(2),(3),(4),(5);
insert into t2 values (11),(12),(13),(14),(15);
(select * from t1 limit 2) union (select * from t2 limit 3) limit 4;
a
1
2
11
12
(select * from t1 limit 2) union (select * from t2 limit 3);
a
1
2
11
12
13
(select * from t1 limit 2) union (select * from t2 limit 20,3);
a
1
2
set SQL_SELECT_LIMIT=2;
(select * from t1 limit 1) union (select * from t2 limit 3);
a
1
11
set SQL_SELECT_LIMIT=DEFAULT;
drop table t1,t2;
CREATE TABLE t1 (
cid smallint(5) unsigned NOT NULL default '0',
cv varchar(250) NOT NULL default '',
PRIMARY KEY  (cid),
UNIQUE KEY cv (cv)
) ;
INSERT INTO t1 VALUES (8,'dummy');
CREATE TABLE t2 (
cid bigint(20) unsigned NOT NULL auto_increment,
cap varchar(255) NOT NULL default '',
PRIMARY KEY  (cid),
KEY cap (cap)
) ;
CREATE TABLE t3 (
gid bigint(20) unsigned NOT NULL auto_increment,
gn varchar(255) NOT NULL default '',
must tinyint(4) default NULL,
PRIMARY KEY  (gid),
KEY gn (gn)
) ;
INSERT INTO t3 VALUES (1,'V1',NULL);
CREATE TABLE t4 (
uid bigint(20) unsigned NOT NULL default '0',
gid bigint(20) unsigned default NULL,
rid bigint(20) unsigned default NULL,
cid bigint(20) unsigned default NULL,
UNIQUE KEY m (uid,gid,rid,cid),
KEY uid (uid),
KEY rid (rid),
KEY cid (cid),
KEY container (gid,rid,cid)
) ;
INSERT INTO t4 VALUES (1,1,NULL,NULL);
CREATE TABLE t5 (
rid bigint(20) unsigned NOT NULL auto_increment,
rl varchar(255) NOT NULL default '',
PRIMARY KEY  (rid),
KEY rl (rl)
) ;
CREATE TABLE t6 (
uid bigint(20) unsigned NOT NULL auto_increment,
un varchar(250) NOT NULL default '',
uc smallint(5) unsigned NOT NULL default '0',
PRIMARY KEY  (uid),
UNIQUE KEY nc (un,uc),
KEY un (un)
) ;
INSERT INTO t6 VALUES (1,'test',8);
SELECT t4.uid, t5.rl, t3.gn as g1, t4.cid, t4.gid as gg FROM t3, t6, t1, t4 left join t5 on t5.rid = t4.rid left join t2 on t2.cid = t4.cid WHERE t3.gid=t4.gid AND t6.uid = t4.uid AND t6.uc  = t1.cid AND t1.cv = "dummy" AND t6.un = "test";
uid	rl	g1	cid	gg
1	NULL	V1	NULL	1
SELECT t4.uid, t5.rl, t3.gn as g1, t4.cid, t4.gid as gg FROM t3, t6, t1, t4 left join t5 on t5.rid = t4.rid left join t2 on t2.cid = t4.cid WHERE t3.gid=t4.gid AND t6.uid = t4.uid AND t3.must IS NOT NULL AND t6.uc  = t1.cid AND t1.cv = "dummy" AND t6.un = "test";
uid	rl	g1	cid	gg
(SELECT t4.uid, t5.rl, t3.gn as g1, t4.cid, t4.gid as gg FROM t3, t6, t1, t4 left join t5 on t5.rid = t4.rid left join t2 on t2.cid = t4.cid WHERE t3.gid=t4.gid AND t6.uid = t4.uid AND t3.must IS NOT NULL AND t6.uc  = t1.cid AND t1.cv = "dummy" AND t6.un = "test") UNION (SELECT t4.uid, t5.rl, t3.gn as g1, t4.cid, t4.gid as gg FROM t3, t6, t1, t4 left join t5 on t5.rid = t4.rid left join t2 on t2.cid = t4.cid WHERE t3.gid=t4.gid AND t6.uid = t4.uid AND t6.uc  = t1.cid AND t1.cv = "dummy" AND t6.un = "test");
uid	rl	g1	cid	gg
1	NULL	V1	NULL	1
drop table t1,t2,t3,t4,t5,t6;
CREATE TABLE t1 (a int not null, b char (10) not null);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
CREATE TABLE t2 (a int not null, b char (10) not null);
insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
create table t3 select a,b from t1 union select a,b from t2;
create table t4 (select a,b from t1) union (select a,b from t2) limit 2;
insert into  t4 select a,b from t1 union select a,b from t2;
insert into  t3 (select a,b from t1) union (select a,b from t2) limit 2;
select * from t3;
a	b
1	a
2	b
3	c
4	d
5	f
6	e
1	a
2	b
select * from t4;
a	b
1	a
2	b
1	a
2	b
3	c
4	d
5	f
6	e
drop table t1,t2,t3,t4;
create table t1 (a int);
insert into t1 values (1),(2),(3);
create table t2 (a int);
insert into t2 values (3),(4),(5);
(SELECT SQL_CALC_FOUND_ROWS * FROM t1) UNION all (SELECT * FROM t2) LIMIT 1;
a
1
select found_rows();
found_rows()
6
(SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1) UNION all (SELECT * FROM t2) LIMIT 2;
a
1
3
select found_rows();
found_rows()
4
(SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1) UNION all (SELECT * FROM t2);
a
1
3
4
5
select found_rows();
found_rows()
4
(SELECT SQL_CALC_FOUND_ROWS * FROM t1) UNION all (SELECT * FROM t2 LIMIT 1);
a
1
2
3
3
select found_rows();
found_rows()
4
(SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1) UNION SELECT * FROM t2 LIMIT 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 '' at line 1
SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1 UNION all SELECT * FROM t2 LIMIT 2;
a
1
3
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 UNION all SELECT * FROM t2 LIMIT 2;
a
1
2
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 UNION SELECT * FROM t2 LIMIT 2;
a
1
2
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 UNION SELECT * FROM t2 LIMIT 100;
a
1
2
3
4
5
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 100 UNION SELECT * FROM t2;
a
1
2
3
4
5
select found_rows();
found_rows()
5
SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1 UNION SELECT * FROM t2;
a
1
3
4
5
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1 UNION SELECT * FROM t2 LIMIT 2;
a
1
3
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 UNION SELECT * FROM t2 LIMIT 2,2;
a
3
4
select found_rows();
found_rows()
6
SELECT SQL_CALC_FOUND_ROWS * FROM t1 limit 2,2 UNION SELECT * FROM t2;
a
3
4
5
select found_rows();
found_rows()
5
SELECT * FROM t1 UNION SELECT * FROM t2 ORDER BY a desc LIMIT 1;
a
5
(SELECT * FROM t1 ORDER by a) UNION ALL (SELECT * FROM t2 ORDER BY a) ORDER BY A desc LIMIT 4;
a
5
4
3
3
(SELECT * FROM t1) UNION all (SELECT SQL_CALC_FOUND_ROWS * FROM t2) LIMIT 1;
ERROR 42000: Incorrect usage/placement of 'SQL_CALC_FOUND_ROWS'
create temporary table t1 select a from t1 union select a from t2;
drop temporary table t1;
create table t1 select a from t1 union select a from t2;
ERROR HY000: You can't specify target table 't1' for update in FROM clause
select a from t1 union select a from t2 order by t2.a;
ERROR 42S02: Unknown table 't2' in order clause
drop table t1,t2;
select length(version()) > 1 as `*` UNION select 2;
*
1
2
create table t1 (a int);
insert into t1 values (0), (3), (1), (2);
explain (select * from t1) union (select * from t1) order by a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
2	UNION	t1	ALL	NULL	NULL	NULL	NULL	4	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	Using filesort
drop table t1;
CREATE TABLE t1 (  id int(3) unsigned default '0') ENGINE=MyISAM;
INSERT INTO t1 (id) VALUES("1");
CREATE TABLE t2 ( id int(3) unsigned default '0',  id_master int(5) default '0',  text1 varchar(5) default NULL,  text2 varchar(5) default NULL) ENGINE=MyISAM;
INSERT INTO t2 (id, id_master, text1, text2) VALUES("1", "1",
"foo1", "bar1");
INSERT INTO t2 (id, id_master, text1, text2) VALUES("2", "1",
"foo2", "bar2");
INSERT INTO t2 (id, id_master, text1, text2) VALUES("3", "1", NULL,
"bar3");
INSERT INTO t2 (id, id_master, text1, text2) VALUES("4", "1",
"foo4", "bar4");
SELECT 1 AS id_master, 1 AS id, NULL AS text1, 'ABCDE' AS text2 UNION SELECT id_master, t2.id, text1, text2 FROM t1 LEFT JOIN t2 ON t1.id = t2.id_master;
id_master	id	text1	text2
1	1	NULL	ABCDE
1	1	foo1	bar1
1	2	foo2	bar2
1	3	NULL	bar3
1	4	foo4	bar4
SELECT 1 AS id_master, 1 AS id, 'ABCDE' AS text1, 'ABCDE' AS text2 UNION SELECT id_master, t2.id, text1, text2 FROM t1 LEFT JOIN t2 ON t1.id = t2.id_master;
id_master	id	text1	text2
1	1	ABCDE	ABCDE
1	1	foo1	bar1
1	2	foo2	bar2
1	3	NULL	bar3
1	4	foo4	bar4
drop table if exists t1,t2;
create table t1 (a int not null primary key auto_increment, b int, key(b));
create table t2 (a int not null primary key auto_increment, b int);
insert into t1 (b) values (1),(2),(2),(3);
insert into t2 (b) values (10),(11),(12),(13);
explain extended (select * from t1 where a=1) union (select * from t2 where a=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	const	PRIMARY	PRIMARY	4	const	1	
2	UNION	t2	const	PRIMARY	PRIMARY	4	const	1	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	(select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where (`test`.`t1`.`a` = 1)) union (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` = 1))
(select * from t1 where a=5) union (select * from t2 where a=1);
a	b
1	10
(select * from t1 where a=5 and a=6) union (select * from t2 where a=1);
a	b
1	10
(select t1.a,t1.b from t1,t2 where t1.a=5) union (select * from t2 where a=1);
a	b
1	10
(select * from t1 where a=1) union (select t1.a,t2.a from t1,t2 where t1.a=t2.a);
a	b
1	1
2	2
3	3
4	4
explain (select * from t1 where a=1 and b=10) union (select straight_join t1.a,t2.a from t1,t2 where t1.a=t2.a);
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	UNION	t1	index	PRIMARY	PRIMARY	4	NULL	4	Using index
2	UNION	t2	index	PRIMARY	PRIMARY	4	NULL	3	Using where; Using index
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
explain (select * from t1 where a=1) union (select * from t1 where b=1);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	const	PRIMARY	PRIMARY	4	const	1	
2	UNION	t1	ref	b	b	5	const	1	Using where
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
drop table t1,t2;
create table t1 (   id int not null auto_increment, primary key (id)   ,user_name text );
create table t2 (    id int not null auto_increment, primary key (id)   ,group_name text );
create table t3 (    id int not null auto_increment, primary key (id)   ,user_id int   ,index user_idx (user_id)   ,foreign key (user_id) references users(id)   ,group_id int   ,index group_idx (group_id)   ,foreign key (group_id) references groups(id) );
insert into t1 (user_name) values ('Tester');
insert into t2 (group_name) values ('Group A');
insert into t2 (group_name) values ('Group B');
insert into t3 (user_id, group_id) values (1,1);
select 1 'is_in_group', a.user_name, c.group_name, b.id from t1 a, t3 b, t2 c where a.id = b.user_id and b.group_id = c.id UNION  select 0 'is_in_group', a.user_name, c.group_name, null from t1 a, t2 c;
is_in_group	user_name	group_name	id
1	Tester	Group A	1
0	Tester	Group A	NULL
0	Tester	Group B	NULL
drop table t1, t2, t3;
create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id union SELECT 0, 0;
pla_id	matintnum
100	a
101	a
102	a
103	b
104	b
105	c
0	0
drop table t1, t2;
create table t1 SELECT "a" as a UNION select "aa" as a;
select * from t1;
a
a
aa
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(2) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT 12 as a UNION select "aa" as a;
select * from t1;
a
12
aa
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varbinary(20) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT 12 as a UNION select 12.2 as a;
select * from t1;
a
12.0
12.2
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` decimal(3,1) NOT NULL default '0.0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t2 (it1 tinyint, it2 tinyint not null, i int not null, ib bigint, f float, d double, y year, da date, dt datetime, sc char(10), sv varchar(10), b blob, tx text);
insert into t2 values (NULL, 1, 3, 4, 1.5, 2.5, 1972, '1972-10-22', '1972-10-22 11:50', 'testc', 'testv', 'tetetetetest', 'teeeeeeeeeeeest');
create table t1 SELECT it2 from t2 UNION select it1 from t2;
select * from t1;
it2
1
NULL
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `it2` tinyint(4) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT it2 from t2 UNION select i from t2;
select * from t1;
it2
1
3
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `it2` int(11) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT i from t2 UNION select f from t2;
select * from t1;
i
3
1.5
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` double default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT f from t2 UNION select d from t2;
select * from t1;
f
1.5
2.5
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `f` double default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT ib from t2 UNION select f from t2;
select * from t1;
ib
4
1.5
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `ib` double default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT ib from t2 UNION select d from t2;
select * from t1;
ib
4
2.5
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `ib` double default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT f from t2 UNION select y from t2;
select * from t1;
f
1.5
1972
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `f` float default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT f from t2 UNION select da from t2;
select * from t1;
f
1.5
1972-10-22
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `f` varbinary(24) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT y from t2 UNION select da from t2;
select * from t1;
y
1972
1972-10-22
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `y` varbinary(10) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT y from t2 UNION select dt from t2;
select * from t1;
y
1972
1972-10-22 11:50:00
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `y` varbinary(19) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT da from t2 UNION select dt from t2;
select * from t1;
da
1972-10-22 00:00:00
1972-10-22 11:50:00
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `da` datetime default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT dt from t2 UNION select sc from t2;
select * from t1;
dt
1972-10-22 11:50:00
testc
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `dt` varbinary(19) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT dt from t2 UNION select sv from t2;
select * from t1;
dt
1972-10-22 11:50:00
testv
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `dt` varbinary(19) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT sc from t2 UNION select sv from t2;
select * from t1;
sc
testc
testv
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `sc` varchar(10) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT dt from t2 UNION select b from t2;
select * from t1;
dt
1972-10-22 11:50:00
tetetetetest
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `dt` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT sv from t2 UNION select b from t2;
select * from t1;
sv
testv
tetetetetest
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `sv` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT i from t2 UNION select d from t2 UNION select b from t2;
select * from t1;
i
3
2.5
tetetetetest
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `i` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT sv from t2 UNION select tx from t2;
select * from t1;
sv
testv
teeeeeeeeeeeest
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `sv` longtext
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 SELECT b from t2 UNION select tx from t2;
select * from t1;
b
tetetetetest
teeeeeeeeeeeest
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `b` longblob
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1,t2;
create table t1 (d decimal(10,1));
create table t2 (d decimal(10,9));
insert into t1 values ("100000000.0");
insert into t2 values ("1.23456780");
create table t3 select * from t2 union select * from t1;
select * from t3;
d
1.234567800
100000000.000000000
show create table t3;
Table	Create Table
t3	CREATE TABLE `t3` (
  `d` decimal(18,9) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1,t2,t3;
create table t1 select 1 union select -1;
select * from t1;
1
1
-1
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `1` bigint(20) NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 select _latin1"test" union select _latin2"testt" ;
ERROR HY000: Illegal mix of collations (latin1_swedish_ci,COERCIBLE) and (latin2_general_ci,COERCIBLE) for operation 'UNION'
create table t1 select _latin2"test" union select _latin2"testt" ;
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `test` varchar(5) character set latin2 NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (s char(200));
insert into t1 values (repeat("1",200));
create table t2 select * from t1;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
insert into t1 select * from t2;
insert into t2 select * from t1;
set local tmp_table_size=1024;
select count(*) from (select * from t1 union all select * from t2 order by 1) b;
count(*)
21
select count(*) from t1;
count(*)
8
select count(*) from t2;
count(*)
13
drop table t1,t2;
set local tmp_table_size=default;
create table t1 (a int, index (a), b int);
insert t1 values (1,1),(2,2),(3,3),(4,4),(5,5);
insert t1 select a+1, a+b from t1;
insert t1 select a+1, a+b from t1;
insert t1 select a+1, a+b from t1;
insert t1 select a+1, a+b from t1;
insert t1 select a+1, a+b from t1;
FLUSH STATUS;
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	0
select count(*) from t1 where a=7;
count(*)
26
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	1
select count(*) from t1 where b=13;
count(*)
10
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	3
select count(*) from t1 where b=13 union select count(*) from t1 where a=7;
count(*)
10
26
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	5
select count(*) from t1 where a=7 union select count(*) from t1 where b=13;
count(*)
26
10
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	7
flush status;
select a from t1 where b not in (1,2,3) union select a from t1 where b not in (4,5,6);
a
4
5
3
6
7
8
9
10
1
2
show status like 'Slow_queries';
Variable_name	Value
Slow_queries	1
drop table t1;
create table t1 (   RID int(11) not null default '0',   IID int(11) not null default '0',    nada varchar(50)  not null,NAME varchar(50) not null,PHONE varchar(50) not null) engine=MyISAM;
insert into t1 ( RID,IID,nada,NAME,PHONE) values (1, 1, 'main', 'a', '111'), (2, 1, 'main', 'b', '222'), (3, 1, 'main', 'c', '333'), (4, 1, 'main', 'd', '444'), (5, 1, 'main', 'e', '555'), (6, 2, 'main', 'c', '333'), (7, 2, 'main', 'd', '454'), (8, 2, 'main', 'e', '555'), (9, 2, 'main', 'f', '666'), (10, 2, 'main', 'g', '777');
select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 A left join t1 B on A.NAME = B.NAME and B.IID = 2 where A.IID = 1 and (A.PHONE <> B.PHONE or B.NAME is null) union select A.NAME, A.PHONE, B.NAME, B.PHONE from t1 B left join t1 A on B.NAME = A.NAME and A.IID = 1 where B.IID = 2 and (A.PHONE <> B.PHONE or A.NAME is null);
NAME	PHONE	NAME	PHONE
a	111	NULL	NULL
b	222	NULL	NULL
d	444	d	454
NULL	NULL	f	666
NULL	NULL	g	777
drop  table t1;
create table t1 (col1 tinyint unsigned, col2 tinyint unsigned);
insert into t1 values (1,2),(3,4),(5,6),(7,8),(9,10);
select col1 n from t1 union select col2 n from t1 order by n;
n
1
2
3
4
5
6
7
8
9
10
alter table t1 add index myindex (col2);
select col1 n from t1 union select col2 n from t1 order by n;
n
1
2
3
4
5
6
7
8
9
10
drop  table t1;
create table t1 (i int);
insert into t1 values (1);
select * from t1 UNION select * from t1;
i
1
select * from t1 UNION ALL select * from t1;
i
1
1
select * from t1 UNION select * from t1 UNION ALL select * from t1;
i
1
1
drop table t1;
select 1 as a union all select 1 union all select 2 union select 1 union all select 2;
a
1
2
2
set sql_select_limit=1;
select 1 union select 2;
1
1
(select 1) union (select 2);
1
1
(select 1) union (select 2) union (select 3) limit 2;
1
1
2
set sql_select_limit=default;
create table t1 (a int);
insert into t1 values (100), (1);
create table t2 (a int);
insert into t2 values (100);
select a from t1 union select a from t2 order by a;
a
1
100
SET SQL_SELECT_LIMIT=1;
select a from t1 union select a from t2 order by a;
a
1
drop table t1, t2;
set sql_select_limit=default;
CREATE TABLE t1 (i int(11) default NULL,c char(1) default NULL,KEY i (i));
CREATE TABLE t2 (i int(11) default NULL,c char(1) default NULL,KEY i (i));
explain (select * from t1) union (select * from t2) order by not_existing_column;
ERROR 42S22: Unknown column 'not_existing_column' in 'order clause'
drop table t1, t2;
CREATE TABLE t1 (uid int(1));
INSERT INTO t1 SELECT 150;
SELECT 'a' UNION SELECT uid FROM t1;
a
a
150
drop table t1;
CREATE TABLE t1 ( ID1 int(10) unsigned NOT NULL DEFAULT '0' , ID2 datetime NOT NULL DEFAULT '0000-00-00 00:00:00' , DATA1 varchar(10) , DATA2 double(5,4) , DATA3 datetime , PRIMARY KEY (ID1,ID2));
CREATE TABLE t2 ( ID int(3) unsigned NOT NULL DEFAULT '0' , DATA1 timestamp DEFAULT '0000-00-00 00:00:00' , PRIMARY KEY (ID));
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1) UNION
(SELECT * FROM t1 AS PARTITIONED, t2 AS
PARTITIONED_B WHERE PARTITIONED_B.ID=PARTITIONED.ID1);
ID1	ID2	DATA1	DATA2	DATA3	ID	DATA1
drop table t1,t2;
create table t1 (a ENUM('Yes', 'No') NOT NULL);
create table t2 (a ENUM('aaa', 'bbb') NOT NULL);
insert into t1 values ('No');
insert into t2 values ('bbb');
create table t3 (a SET('Yes', 'No') NOT NULL);
create table t4 (a SET('aaa', 'bbb') NOT NULL);
insert into t3 values (1);
insert into t4 values (3);
select "1" as a union select a from t1;
a
1
No
select a as a from t1 union select "1";
a
No
1
select a as a from t2 union select a from t1;
a
bbb
No
select "1" as a union select a from t3;
a
1
Yes
select a as a from t3 union select "1";
a
Yes
1
select a as a from t4 union select a from t3;
a
aaa,bbb
Yes
select a as a from t1 union select a from t4;
a
No
aaa,bbb
drop table t1,t2,t3,t4;
create table t1 as
(select _latin1'test') union
(select _latin1'TEST') union
(select _latin1'TeST');
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `test` varchar(4) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1;
count(*)
1
drop table t1;
create table t1 as
(select _latin1'test' collate latin1_bin) union
(select _latin1'TEST') union
(select _latin1'TeST');
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `_latin1'test' collate latin1_bin` varchar(4) character set latin1 collate latin1_bin NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1;
count(*)
3
drop table t1;
create table t1 as
(select _latin1'test') union
(select _latin1'TEST' collate latin1_bin) union
(select _latin1'TeST');
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `test` varchar(4) character set latin1 collate latin1_bin NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1;
count(*)
3
drop table t1;
create table t1 as
(select _latin1'test') union
(select _latin1'TEST') union
(select _latin1'TeST' collate latin1_bin);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `test` varchar(4) character set latin1 collate latin1_bin NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select count(*) from t1;
count(*)
3
drop table t1;
create table t2 (
a char character set latin1 collate latin1_swedish_ci,
b char character set latin1 collate latin1_german1_ci);
create table t1 as
(select a from t2) union
(select b from t2);
ERROR HY000: Illegal mix of collations for operation 'UNION'
create table t1 as
(select a collate latin1_german1_ci from t2) union
(select b from t2);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a collate latin1_german1_ci` varchar(1) character set latin1 collate latin1_german1_ci default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 as
(select a from t2) union
(select b collate latin1_german1_ci from t2);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(1) character set latin1 collate latin1_german1_ci default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 as
(select a from t2) union
(select b from t2) union
(select 'c' collate latin1_german1_ci from t2);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` varchar(1) character set latin1 collate latin1_german1_ci default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
drop table t2;
create table t1(a1 int, f1 char(10));
create table t2
select f2,a1 from (select a1, CAST('2004-12-31' AS DATE) f2 from t1) a
union
select f2,a1 from (select a1, CAST('2004-12-31' AS DATE) f2 from t1) a
order by f2, a1;
show columns from t2;
Field	Type	Null	Key	Default	Extra
f2	date	YES		NULL	
a1	int(11)	YES		NULL	
drop table t1, t2;
create table t1 (f1 int);
create table t2 (f1 int, f2 int ,f3 date);
create table t3 (f1 int, f2 char(10));
create table t4
(
select t2.f3 as sdate
from t1
left outer join t2 on (t1.f1 = t2.f1)
inner join t3 on (t2.f2 = t3.f1)
order by t1.f1, t3.f1, t2.f3
)
union
(
select cast('2004-12-31' as date) as sdate
from t1
left outer join t2 on (t1.f1 = t2.f1)
inner join t3 on (t2.f2 = t3.f1)
group by t1.f1
order by t1.f1, t3.f1, t2.f3
)
order by sdate;
show columns from t4;
Field	Type	Null	Key	Default	Extra
sdate	date	YES		NULL	
drop table t1, t2, t3, t4;
create table t1 (a int not null, b char (10) not null);
insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
select * from ((select * from t1 limit 1)) a;
a	b
1	a
select * from ((select * from t1 limit 1) union (select * from t1 limit 1)) a;
a	b
1	a
select * from ((select * from t1 limit 1) union (select * from t1 limit 1) union (select * from t1 limit 1)) a;
a	b
1	a
select * from ((((select * from t1))) union (select * from t1) union (select * from t1)) a;
a	b
1	a
2	b
3	c
select * from ((select * from t1) union (((select * from t1))) union (select * from t1)) a;
a	b
1	a
2	b
3	c
drop table t1;
set @val:=6;
select concat('value is: ', @val) union select 'some text';
concat('value is: ', @val)
value is: 6
some text
CREATE TABLE t1 (
a ENUM('ä','ö','ü') character set utf8 not null default 'ü',
b ENUM("one", "two") character set utf8,
c ENUM("one", "two")
);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` enum('ä','ö','ü') character set utf8 NOT NULL default 'ü',
  `b` enum('one','two') character set utf8 default NULL,
  `c` enum('one','two') default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values ('ä', 'one', 'one'), ('ö', 'two', 'one'), ('ü', NULL, NULL);
create table t2 select NULL union select a from t1;
show columns from t2;
Field	Type	Null	Key	Default	Extra
NULL	enum('ä','ö','ü')	YES		NULL	
drop table t2;
create table t2 select a from t1 union select NULL;
show columns from t2;
Field	Type	Null	Key	Default	Extra
a	enum('ä','ö','ü')	YES		NULL	
drop table t2;
create table t2 select a from t1 union select a from t1;
show columns from t2;
Field	Type	Null	Key	Default	Extra
a	varchar(1)	NO			
drop table t2;
create table t2 select a from t1 union select c from t1;
ERROR HY000: Illegal mix of collations (utf8_general_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation 'UNION'
create table t2 select a from t1 union select b from t1;
show columns from t2;
Field	Type	Null	Key	Default	Extra
a	varchar(3)	YES		NULL	
drop table t2, t1;
create table t1 (a varchar(5));
create table t2 select * from t1 union select 'abcdefghijkl';
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` varchar(12) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
select row_format from information_schema.TABLES where table_schema="test" and table_name="t2";
row_format
Dynamic
alter table t2 ROW_FORMAT=fixed;
show create table t2;
Table	Create Table
t2	CREATE TABLE `t2` (
  `a` varchar(12) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED
drop table t1,t2;
CREATE TABLE t1 (a mediumtext);
CREATE TABLE t2 (b varchar(20));
INSERT INTO t1 VALUES ('a'),('b');
SELECT left(a,100000000) FROM t1 UNION  SELECT b FROM t2;
left(a,100000000)
a
b
create table t3 SELECT left(a,100000000) FROM t1 UNION  SELECT b FROM t2;
show create table t3;
Table	Create Table
t3	CREATE TABLE `t3` (
  `left(a,100000000)` longtext
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop tables t1,t2,t3;
create table t1 ( id int not null auto_increment, primary key (id), col1 int);
insert into t1 (col1) values (2),(3),(4),(5),(6);
select 99 union all select id from t1 order by 1;
99
1
2
3
4
5
99
select id from t1 union all select 99 order by 1;
id
1
2
3
4
5
99
drop table t1;
