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 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
3	c
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
3	c
3	c
4	d
5	f
6	e
7	g
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 SELECT's can not 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
Warnings:
Note	1003	(select high_priority 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	
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;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
2	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
explain select 1 union select a,b from t1 union select 1;
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	UNION	t1	ALL	NULL	NULL	NULL	NULL	4	
3	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
explain select a,b from t1 union select 1 limit 0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
2	UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
select a,b from t1 into outfile 'skr' union select a,b from t2;
ERROR HY000: Wrong usage of UNION and INTO
select a,b from t1 order by a union select a,b from t2;
ERROR HY000: Wrong usage of UNION and ORDER BY
insert into t3 select a from t1 order by a union select a from t2;
ERROR HY000: Wrong 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: Wrong 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`)
) TYPE=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
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: Wrong usage/placement of 'SQL_CALC_FOUND_ROWS'
drop table t1,t2;
CREATE TABLE t1 (  id int(3) unsigned default '0') TYPE=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) TYPE=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		bar1
1	2		bar2
1	3	NULL	bar3
1	4		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	
Warnings:
Note	1003	(select high_priority 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 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
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
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;
