mirror of
https://github.com/MariaDB/server.git
synced 2025-01-17 20:42:30 +01:00
2901c3b8fa
Use server character set if --default-character-set is not used Added convert_string() for more efficient alloc+character-set convert of strings BitKeeper/deleted/.del-convert.result~a3b56e1db6f498e9: Delete: mysql-test/r/convert.result BitKeeper/deleted/.del-convert.test~f4ceb743194dfe72: Delete: mysql-test/t/convert.test BitKeeper/deleted/.del-make_win_src_distribution.old~5c9ebdc4a852b43b: Delete: scripts/make_win_src_distribution.old client/mysql.cc: Use server character set if --default-character-set is not used client/mysqltest.c: Code cleanup (merge identical code) More debug messages heap/hp_create.c: After merge fix include/m_ctype.h: After merge fix include/my_global.h: Remove size_str (we already have size_s) include/mysql_com.h: After merge fix libmysql/libmysql.c: After merge fix libmysqld/Makefile.am: After merge fix mysql-test/r/auto_increment.result: After merge fix mysql-test/r/create.result: After merge fix mysql-test/r/ctype_latin1_de.result: After merge fix mysql-test/r/distinct.result: After merge fix mysql-test/r/drop.result: After merge fix mysql-test/r/fulltext.result: After merge fix mysql-test/r/func_gconcat.result: After merge fix mysql-test/r/func_str.result: After merge fix mysql-test/r/func_test.result: After merge fix mysql-test/r/grant.result: After merge fix mysql-test/r/group_by.result: After merge fix mysql-test/r/handler.result: After merge fix mysql-test/r/heap.result: After merge fix mysql-test/r/heap_btree.result: After merge fix mysql-test/r/heap_hash.result: After merge fix mysql-test/r/innodb.result: After merge fix mysql-test/r/insert.result: After merge fix mysql-test/r/insert_select.result: After merge fix mysql-test/r/join_outer.result: After merge fix mysql-test/r/key.result: After merge fix mysql-test/r/key_cache.result: After merge fix mysql-test/r/loaddata.result: After merge fix mysql-test/r/myisam.result: After merge fix mysql-test/r/null.result: After merge fix mysql-test/r/null_key.result: After merge fix mysql-test/r/order_by.result: After merge fix mysql-test/r/rpl_do_grant.result: After merge fix mysql-test/r/rpl_error_ignored_table.result: After merge fix mysql-test/r/rpl_ignore_grant.result: After merge fix mysql-test/r/rpl_loaddata.result: After merge fix mysql-test/r/rpl_log.result: After merge fix mysql-test/r/rpl_log_pos.result: After merge fix mysql-test/r/rpl_max_relay_size.result: After merge fix mysql-test/r/rpl_replicate_do.result: After merge fix mysql-test/r/rpl_reset_slave.result: After merge fix mysql-test/r/rpl_rotate_logs.result: After merge fix mysql-test/r/rpl_user_variables.result: After merge fix mysql-test/r/select.result: After merge fix mysql-test/r/select_safe.result: After merge fix mysql-test/r/subselect.result: After merge fix mysql-test/r/type_blob.result: After merge fix mysql-test/r/type_decimal.result: After merge fix mysql-test/r/type_float.result: After merge fix mysql-test/r/type_ranges.result: After merge fix mysql-test/r/type_time.result: After merge fix mysql-test/r/type_uint.result: After merge fix mysql-test/r/union.result: After merge fix mysql-test/r/warnings.result: After merge fix mysql-test/t/auto_increment.test: After merge fix mysql-test/t/case.test: After merge fix mysql-test/t/ctype_collate.test: After merge fix mysql-test/t/ctype_latin1_de.test: After merge fix mysql-test/t/drop.test: After merge fix mysql-test/t/func_in.test: After merge fix mysql-test/t/func_set.test: After merge fix mysql-test/t/func_str.test: After merge fix mysql-test/t/func_test.test: After merge fix mysql-test/t/grant.test: After merge fix mysql-test/t/group_by.test: After merge fix mysql-test/t/handler.test: After merge fix mysql-test/t/heap.test: After merge fix mysql-test/t/heap_btree.test: After merge fix mysql-test/t/heap_hash.test: After merge fix mysql-test/t/innodb.test: After merge fix mysql-test/t/insert_select.test: After merge fix mysql-test/t/key.test: After merge fix mysql-test/t/key_cache.test: After merge fix mysql-test/t/lock_tables_lost_commit-master.opt: After merge fix mysql-test/t/lock_tables_lost_commit.test: After merge fix mysql-test/t/myisam.test: After merge fix mysql-test/t/row.test: After merge fix mysql-test/t/subselect.test: After merge fix mysql-test/t/type_decimal.test: After merge fix mysql-test/t/type_ranges.test: After merge fix mysql-test/t/type_uint.test: After merge fix mysql-test/t/variables.test: After merge fix mysql-test/t/warnings.test: After merge fix scripts/make_win_src_distribution.sh: after merge fixes sql-common/client.c: After merge fix Change my_connect() to use poll() If character set is not given, use servers character set. sql/field.cc: After merge fix Don't give warnings when storing data in fields in optimizer. sql/ha_myisammrg.h: After merge fix sql/log.cc: After merge fix sql/log_event.cc: After merge fix sql/mysqld.cc: After merge fix sql/opt_range.cc: After merge fix sql/set_var.cc: Code cleanup Fixed wrong usage of base_names (like medium.key_buffer) that caused core dumps sql/set_var.h: Fixed wrong usage of base_names (like medium.key_buffer) that caused core dumps sql/slave.cc: After merge fix sql/sql_acl.cc: After merge fix Code cleanup sql/sql_class.cc: Added convert_string() for more efficient alloc+character-set convert of strings Add cached flags to avoid calling mysql_charset_same() during parsing. sql/sql_class.h: Added convert_string() for more efficient alloc+character-set convert of strings Add cached flags to avoid calling mysql_charset_same() during parsing. sql/sql_handler.cc: After merge fix sql/sql_lex.h: After merge fix sql/sql_parse.cc: Optimize and fix memory reference errors reported by valgrind sql/sql_repl.cc: After merge fix sql/sql_yacc.yy: After merge fix Avoid calling mysql_charset_same() when parsing identifiers strings/ctype-latin1.c: Port latin_de conversion code from 4.0
386 lines
12 KiB
Text
386 lines
12 KiB
Text
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 (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
|
|
(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()
|
|
6
|
|
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 ( 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 (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
|
|
(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;
|