mariadb/mysql-test/t/union.test
unknown 034b44cb9f Merge with 4.0.14
BitKeeper/etc/logging_ok:
  auto-union
scripts/make_win_src_distribution.old:
  Merge rename: scripts/make_win_src_distribution.sh -> scripts/make_win_src_distribution.old
BUILD/compile-pentium-debug-max:
  Auto merged
BitKeeper/deleted/.del-sel000001.result~383913ae4505ec86:
  Auto merged
BitKeeper/deleted/.del-sel000001.test~9567c1646058cc:
  Auto merged
Build-tools/Bootstrap:
  Auto merged
Build-tools/Do-compile:
  Auto merged
Docs/Makefile.am:
  Auto merged
client/get_password.c:
  Auto merged
client/mysql.cc:
  Auto merged
client/mysqltest.c:
  Auto merged
extra/perror.c:
  Auto merged
include/config-win.h:
  Auto merged
include/my_sys.h:
  Auto merged
innobase/btr/btr0cur.c:
  Auto merged
innobase/btr/btr0pcur.c:
  Auto merged
innobase/buf/buf0buf.c:
  Auto merged
innobase/buf/buf0flu.c:
  Auto merged
innobase/dict/dict0dict.c:
  Auto merged
innobase/dict/dict0load.c:
  Auto merged
innobase/include/buf0buf.h:
  Auto merged
innobase/include/log0recv.h:
  Auto merged
innobase/include/row0sel.h:
  Auto merged
innobase/include/srv0srv.h:
  Auto merged
innobase/include/ut0mem.h:
  Auto merged
innobase/lock/lock0lock.c:
  Auto merged
innobase/log/log0log.c:
  Auto merged
innobase/mem/mem0pool.c:
  Auto merged
innobase/os/os0file.c:
  Auto merged
innobase/row/row0mysql.c:
  Auto merged
innobase/row/row0sel.c:
  Auto merged
innobase/srv/srv0srv.c:
  Auto merged
innobase/srv/srv0start.c:
  Auto merged
innobase/trx/trx0sys.c:
  Auto merged
innobase/trx/trx0trx.c:
  Auto merged
innobase/ut/ut0mem.c:
  Auto merged
innobase/ut/ut0ut.c:
  Auto merged
myisam/ft_boolean_search.c:
  Auto merged
myisam/mi_check.c:
  Auto merged
myisam/mi_extra.c:
  Auto merged
myisam/mi_key.c:
  Auto merged
myisam/myisamdef.h:
  Auto merged
myisammrg/myrg_queue.c:
  Auto merged
mysql-test/mysql-test-run.sh:
  Auto merged
mysql-test/r/ctype_latin1_de.result:
  Auto merged
mysql-test/r/flush.result:
  Auto merged
mysql-test/r/func_time.result:
  Auto merged
mysql-test/r/grant_cache.result:
  Auto merged
mysql-test/r/join.result:
  Auto merged
mysql-test/r/join_outer.result:
  Auto merged
mysql-test/r/range.result:
  Auto merged
mysql-test/r/rpl000018.result:
  Auto merged
mysql-test/r/rpl_insert_id.result:
  Auto merged
mysql-test/r/rpl_master_pos_wait.result:
  Auto merged
mysql-test/r/rpl_relayspace.result:
  Auto merged
mysql-test/r/select_safe.result:
  Auto merged
mysql-test/r/symlink.result:
  Auto merged
mysql-test/r/type_date.result:
  Auto merged
mysql-test/r/type_datetime.result:
  Auto merged
mysql-test/t/alias.test:
  Auto merged
mysql-test/t/ctype_latin1_de.test:
  Auto merged
mysql-test/t/fulltext_left_join.test:
  Auto merged
mysql-test/t/func_time.test:
  Auto merged
mysql-test/t/handler.test:
  Auto merged
mysql-test/t/heap.test:
  Auto merged
mysql-test/t/join.test:
  Auto merged
mysql-test/t/join_outer.test:
  Auto merged
mysql-test/t/order_by.test:
  Auto merged
mysql-test/t/range.test:
  Auto merged
mysql-test/t/rpl000001.test:
  Auto merged
mysql-test/t/rpl000018.test:
  Auto merged
mysql-test/t/rpl_insert_id.test:
  Auto merged
mysql-test/t/sel000100.test:
  Auto merged
mysql-test/t/select_safe.test:
  Auto merged
mysql-test/t/type_date.test:
  Auto merged
mysql-test/t/type_datetime.test:
  Auto merged
mysql-test/t/user_var.test:
  Auto merged
mysys/default.c:
  Auto merged
mysys/mf_format.c:
  Auto merged
mysys/my_getopt.c:
  Auto merged
mysys/thr_lock.c:
  Auto merged
mysys/tree.c:
  Auto merged
scripts/Makefile.am:
  Auto merged
scripts/mysql_install_db.sh:
  Auto merged
scripts/mysqld_safe.sh:
  Auto merged
sql/Makefile.am:
  Auto merged
sql/field_conv.cc:
  Auto merged
sql/ha_innodb.h:
  Auto merged
sql/ha_myisam.cc:
  Auto merged
sql/ha_myisammrg.h:
  Auto merged
sql/handler.cc:
  Auto merged
sql/handler.h:
  Auto merged
sql/item.h:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/item_timefunc.cc:
  Auto merged
sql/net_serv.cc:
  Auto merged
sql/nt_servc.cc:
  Auto merged
sql/opt_range.cc:
  Auto merged
sql/sql_base.cc:
  Auto merged
sql/sql_cache.h:
  Auto merged
sql/sql_db.cc:
  Auto merged
sql/sql_delete.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged
sql/sql_list.h:
  Auto merged
sql/sql_load.cc:
  Auto merged
sql/sql_rename.cc:
  Auto merged
sql/sql_repl.h:
  Auto merged
sql/sql_update.cc:
  Auto merged
sql/table.cc:
  Auto merged
sql/table.h:
  Auto merged
sql/uniques.cc:
  Auto merged
support-files/mysql.spec.sh:
  Auto merged
vio/viosocket.c:
  Auto merged
BitKeeper/deleted/.del-ctype-latin1_de.c~c5d8f9208bceb98e:
  merge
BitKeeper/deleted/.del-mini_client.cc~8677895ec8169183:
  merge
acinclude.m4:
  Merge with 4.0 (openssl patch)
client/mysqlbinlog.cc:
  Merge with 4.0 in which we had added code from 4.1
  (We are basicly only using the 4.1 code here)
configure.in:
  Keep 4.1 file
heap/hp_open.c:
  merge with 4.0
include/my_base.h:
  merge with 4.0
include/my_global.h:
  merge with 4.0
include/mysqld_error.h:
  merge with 4.0
innobase/ha/ha0ha.c:
  merge with 4.0
  (Code should be same but we use indentaion from 4.0)
innobase/log/log0recv.c:
  merge with 4.0
libmysql/libmysql.c:
  Remove with 4.0 code that was ported from 4.1
libmysqld/lib_sql.cc:
  merge with 4.0
myisam/mi_open.c:
  Remove 4.0 specific code
myisam/myisamchk.c:
  merge with 4.0
myisammrg/myrg_rkey.c:
  merge with 4.0
mysql-test/r/alter_table.result:
  May need to be fixed after merge
mysql-test/r/create.result:
  May need to be fixed after merge
mysql-test/r/distinct.result:
  May need to be fixed after merge
mysql-test/r/drop.result:
  May need to be fixed after merge
mysql-test/r/fulltext.result:
  May need to be fixed after merge
mysql-test/r/func_set.result:
  May need to be fixed after merge
mysql-test/r/func_str.result:
  May need to be fixed after merge
mysql-test/r/func_test.result:
  May need to be fixed after merge
mysql-test/r/grant.result:
  May need to be fixed after merge
mysql-test/r/group_by.result:
  May need to be fixed after merge
mysql-test/r/handler.result:
  May need to be fixed after merge
mysql-test/r/heap.result:
  May need to be fixed after merge
mysql-test/r/innodb.result:
  May need to be fixed after merge
mysql-test/r/insert.result:
  May need to be fixed after merge
mysql-test/r/insert_select.result:
  May need to be fixed after merge
mysql-test/r/key_diff.result:
  May need to be fixed after merge
mysql-test/r/merge.result:
  May need to be fixed after merge
mysql-test/r/myisam.result:
  May need to be fixed after merge
mysql-test/r/order_by.result:
  May need to be fixed after merge
mysql-test/r/query_cache.result:
  May need to be fixed after merge
mysql-test/r/rpl_flush_log_loop.result:
  May need to be fixed after merge
mysql-test/r/rpl_loaddata.result:
  May need to be fixed after merge
mysql-test/r/rpl_log.result:
  May need to be fixed after merge
mysql-test/r/rpl_log_pos.result:
  May need to be fixed after merge
mysql-test/r/rpl_rotate_logs.result:
  May need to be fixed after merge
mysql-test/r/select.result:
  May need to be fixed after merge
mysql-test/r/union.result:
  May need to be fixed after merge
mysql-test/r/user_var.result:
  May need to be fixed after merge
mysql-test/t/alter_table.test:
  merge with 4.0
mysql-test/t/create.test:
  merge with 4.0
mysql-test/t/distinct.test:
  merge with 4.0
mysql-test/t/drop.test:
  merge with 4.0
mysql-test/t/flush.test:
  merge with 4.0
mysql-test/t/fulltext.test:
  merge with 4.0
mysql-test/t/func_set.test:
  merge with 4.0
mysql-test/t/func_str.test:
  merge with 4.0
mysql-test/t/func_test.test:
  merge with 4.0
mysql-test/t/grant.test:
  merge with 4.0
mysql-test/t/grant_cache.test:
  merge with 4.0
mysql-test/t/innodb.test:
  Add back EXPLAIN and SHOW KEYS statements, but make them independent of number of rows returned by InnoDB
mysql-test/t/insert.test:
  merge with 4.0
mysql-test/t/insert_select.test:
  merge with 4.0
mysql-test/t/merge.test:
  merge with 4.0
mysql-test/t/query_cache.test:
  merge with 4.0
mysql-test/t/rpl_flush_log_loop.test:
  merge with 4.0
mysql-test/t/rpl_loaddata.test:
  merge with 4.0
mysql-test/t/rpl_rotate_logs.test:
  merge with 4.0
mysql-test/t/select.test:
  merge with 4.0
mysql-test/t/symlink.test:
  merge with 4.0
mysql-test/t/union.test:
  merge with 4.0
mysys/charset.c:
  merge with 4.0
scripts/mysql_fix_privilege_tables.sh:
  merge with 4.0 (Add quoting for some variables)
sql/field.h:
  merge with 4.0
sql/ha_innodb.cc:
  merge with 4.0
sql/item_cmpfunc.cc:
  merge with 4.0
sql/item_cmpfunc.h:
  merge with 4.0
sql/item_func.h:
  merge with 4.0
sql/item_strfunc.cc:
  merge with 4.0
  Fixed null handling with ELT()
sql/item_timefunc.h:
  merge with 4.0
sql/lex.h:
  merge with 4.0
sql/log.cc:
  merge with 4.0
sql/log_event.cc:
  Merge with 4.0
  Cleanups:
  - Indentation
  - #endif comments
  - Replace strmov() with *pos++= for two byte strings
  - Moved variable declarations to start of functions
  - Merged identical code (LOAD_EVENT)
  - Added casts when subtracting pointers
  Did a full diff between this and 4.0 to ensure that the file is correct after merge.
sql/log_event.h:
  merge with 4.0
sql/mysql_priv.h:
  merge with 4.0
sql/mysqld.cc:
  merge with 4.0
sql/repl_failsafe.cc:
  merge with 4.0
sql/set_var.cc:
  merge with 4.0
sql/set_var.h:
  merge with 4.0
sql/share/czech/errmsg.txt:
  merge with 4.0
sql/share/danish/errmsg.txt:
  merge with 4.0
sql/share/dutch/errmsg.txt:
  merge with 4.0
sql/share/english/errmsg.txt:
  merge with 4.0
sql/share/estonian/errmsg.txt:
  merge with 4.0
sql/share/french/errmsg.txt:
  merge with 4.0
sql/share/german/errmsg.txt:
  merge with 4.0
sql/share/greek/errmsg.txt:
  merge with 4.0
sql/share/hungarian/errmsg.txt:
  merge with 4.0
sql/share/italian/errmsg.txt:
  merge with 4.0
sql/share/japanese/errmsg.txt:
  merge with 4.0
sql/share/korean/errmsg.txt:
  merge with 4.0
sql/share/norwegian-ny/errmsg.txt:
  merge with 4.0
sql/share/norwegian/errmsg.txt:
  merge with 4.0
sql/share/polish/errmsg.txt:
  merge with 4.0
sql/share/portuguese/errmsg.txt:
  merge with 4.0
sql/share/romanian/errmsg.txt:
  merge with 4.0
sql/share/russian/errmsg.txt:
  merge with 4.0
sql/share/slovak/errmsg.txt:
  merge with 4.0
sql/share/spanish/errmsg.txt:
  merge with 4.0
sql/share/swedish/errmsg.txt:
  merge with 4.0
sql/share/ukrainian/errmsg.txt:
  merge with 4.0
sql/slave.cc:
  Merge + some indentation fixes
sql/slave.h:
  merge with 4.0
sql/sql_acl.cc:
  merge with 4.0
  Some end space removal to make it easier to do future merges
sql/sql_acl.h:
  merge with 4.0
sql/sql_cache.cc:
  merge with 4.0
sql/sql_class.h:
  merge with 4.0
sql/sql_handler.cc:
  merge with 4.0
sql/sql_lex.cc:
  merge with 4.0
sql/sql_lex.h:
  merge with 4.0
sql/sql_parse.cc:
  merge with 4.0
sql/sql_repl.cc:
  merge with 4.0
sql/sql_select.cc:
  merge with 4.0
sql/sql_table.cc:
  merge with 4.0
sql/sql_union.cc:
  Merge with 4.0
  Note that I couldn't find out how to merge OPTION_FOUND_ROWS handling so this has to be fixed later
sql/sql_yacc.yy:
  merge with 4.0
  Removed end space to make merge easier
vio/Makefile.am:
  merge with 4.0
2003-08-11 22:44:43 +03:00

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Text

#
# Test of unions
#
--disable_warnings
drop table if exists t1,t2,t3,t4,t5,t6;
--enable_warnings
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;
select a,b from t1 union all select a,b from t2;
select a,b from t1 union all select a,b from t2 order by b;
select a,b from t1 union all select a,b from t2 union select 7,'g';
select 0,'#' union select a,b from t1 union all select a,b from t2 union select 7,'gg';
select a,b from t1 union select a,b from t1;
select 't1',b,count(*) from t1 group by b UNION select 't2',b,count(*) from t2 group by b;
# Test alternate syntax for unions
(select a,b from t1 limit 2) union all (select a,b from t2 order by a) limit 4;
(select a,b from t1 limit 2) union all (select a,b from t2 order by a limit 1);
(select a,b from t1 limit 2) union all (select a,b from t2 order by a limit 1) order by b desc;
--error 1248
(select a,b from t1 limit 2) union all (select a,b from t2 order by a limit 1) order by t1.b;
explain (select a,b from t1 limit 2) union all (select a,b from t2 order by 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;
select found_rows();
select sql_calc_found_rows a,b from t1 union all select a,b from t2 limit 2;
select found_rows();
#
# Test some error conditions with UNION
#
explain select a,b from t1 union all select a,b from t2;
--error 1054
explain select xx from t1 union select 1;
explain select a,b from t1 union select 1;
explain select 1 union select a,b from t1 union select 1;
explain select a,b from t1 union select 1 limit 0;
--error 1221
select a,b from t1 into outfile 'skr' union select a,b from t2;
--error 1221
select a,b from t1 order by a union select a,b from t2;
--error 1221
insert into t3 select a from t1 order by a union select a from t2;
--error 1222
create table t3 select a,b from t1 union select a from t2;
--error 1222
select a,b from t1 union select a from t2;
--error 1222
select * from t1 union select a from t2;
--error 1222
select a from t1 union select * from t2;
--error 1234
select * from t1 union select SQL_BUFFER_RESULT * from t2;
# Test CREATE, INSERT and REPLACE
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;
#
# Test some unions without tables
#
--error 1096
select * union select 1;
select 1 as a,(select a union select a);
--error 1054
(select 1) union (select 2) order by 0;
SELECT @a:=1 UNION SELECT @a:=@a+1;
--error 1054
(SELECT 1) UNION (SELECT 2) ORDER BY (SELECT a);
(SELECT 1,3) UNION (SELECT 2,1) ORDER BY (SELECT 2);
#
# Test bug reported by joc@presence-pc.com
#
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';
SELECT pseudo1 FROM t1 WHERE pseudo1='joce' UNION SELECT pseudo1 FROM t1 WHERE pseudo='joce';
SELECT * FROM t1 WHERE pseudo1='joce' UNION SELECT * FROM t1 WHERE pseudo='joce' order by pseudo desc,pseudo1 desc;
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION SELECT pseudo FROM t1 WHERE pseudo1='joce';
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION ALL SELECT pseudo FROM t1 WHERE pseudo1='joce';
SELECT pseudo1 FROM t1 WHERE pseudo='joce' UNION SELECT 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;
(select * from t1 limit 2) union (select * from t2 limit 3);
(select * from t1 limit 2) union (select * from t2 limit 20,3);
set SQL_SELECT_LIMIT=2;
(select * from t1 limit 1) union (select * from t2 limit 3);
set SQL_SELECT_LIMIT=DEFAULT;
drop table t1,t2;
#
# Test error with left join
#
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";
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";
(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");
drop table t1,t2,t3,t4,t5,t6;
#
# Test insert ... SELECT with UNION
#
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;
select * from t4;
drop table t1,t2,t3,t4;
#
# Test for another bug with UNION and LEFT JOIN
#
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;
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;
drop table if exists t1,t2;
#
# Test of bug when using the same table multiple times
#
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);
(select * from t1 where a=5) union (select * from t2 where a=1);
(select * from t1 where a=5 and a=6) union (select * from t2 where a=1);
(select t1.a,t1.b from t1,t2 where t1.a=5) union (select * from t2 where a=1);
(select * from t1 where a=1) union (select t1.a,t2.a from t1,t2 where t1.a=t2.a);
explain (select * from t1 where a=1 and b=10) union (select t1.a,t2.a from t1,t2 where t1.a=t2.a);
explain (select * from t1 where a=1) union (select * from t1 where b=1);
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;
drop table t1, t2, t3;