drop table if exists t1,t2; CREATE TABLE t1 (c int not null, d char (10) not null); insert into t1 values(1,""),(2,"a"),(3,"b"); CREATE TEMPORARY TABLE t1 (a int not null, b char (10) not null); insert into t1 values(4,"e"),(5,"f"),(6,"g"); alter table t1 rename t2; select * from t1; c d 1 2 a 3 b select * from t2; a b 4 e 5 f 6 g CREATE TABLE t2 (x int not null, y int not null); alter table t2 rename t1; select * from t1; a b 4 e 5 f 6 g create TEMPORARY TABLE t2 engine=heap select * from t1; create TEMPORARY TABLE IF NOT EXISTS t2 (a int) engine=heap; CREATE TEMPORARY TABLE t1 (a int not null, b char (10) not null); ERROR 42S01: Table 't1' already exists ALTER TABLE t1 RENAME t2; ERROR 42S01: Table 't2' already exists select * from t2; a b 4 e 5 f 6 g alter table t2 add primary key (a,b); drop table t1,t2; select * from t1; c d 1 2 a 3 b drop table t2; create temporary table t1 select *,2 as "e" from t1; select * from t1; c d e 1 2 2 a 2 3 b 2 drop table t1; drop table t1; CREATE TABLE t1 (pkCrash INTEGER PRIMARY KEY,strCrash VARCHAR(255)); INSERT INTO t1 ( pkCrash, strCrash ) VALUES ( 1, '1'); SELECT CONCAT_WS(pkCrash, strCrash) FROM t1; CONCAT_WS(pkCrash, strCrash) 1 drop table t1; create temporary table t1 select 1 as 'x'; drop table t1; CREATE TABLE t1 (x INT); INSERT INTO t1 VALUES (1), (2), (3); CREATE TEMPORARY TABLE tmp SELECT *, NULL FROM t1; drop table t1; create temporary table t1 (id int(10) not null unique); create temporary table t2 (id int(10) not null primary key, val int(10) not null); insert into t1 values (1),(2),(4); insert into t2 values (1,1),(2,1),(3,1),(4,2); select one.id, two.val, elt(two.val,'one','two') from t1 one, t2 two where two.id=one.id order by one.id; id val elt(two.val,'one','two') 1 1 one 2 1 one 4 2 two drop table t1,t2; create temporary table t1 (a int not null); insert into t1 values (1),(1); alter table t1 add primary key (a); ERROR 23000: Duplicate entry '1' for key 1 drop table t1; CREATE TABLE t1 ( d datetime default NULL ) ENGINE=MyISAM; INSERT INTO t1 VALUES ('2002-10-24 14:50:32'),('2002-10-24 14:50:33'),('2002-10-24 14:50:34'),('2002-10-24 14:50:34'),('2002-10-24 14:50:34'),('2002-10-24 14:50:35'),('2002-10-24 14:50:35'),('2002-10-24 14:50:35'),('2002-10-24 14:50:35'),('2002-10-24 14:50:36'),('2002-10-24 14:50:36'),('2002-10-24 14:50:36'),('2002-10-24 14:50:36'),('2002-10-24 14:50:37'),('2002-10-24 14:50:37'),('2002-10-24 14:50:37'),('2002-10-24 14:50:37'),('2002-10-24 14:50:38'),('2002-10-24 14:50:38'),('2002-10-24 14:50:38'),('2002-10-24 14:50:39'),('2002-10-24 14:50:39'),('2002-10-24 14:50:39'),('2002-10-24 14:50:39'),('2002-10-24 14:50:40'),('2002-10-24 14:50:40'),('2002-10-24 14:50:40'); flush status; select * from t1 group by d; d 2002-10-24 14:50:32 2002-10-24 14:50:33 2002-10-24 14:50:34 2002-10-24 14:50:35 2002-10-24 14:50:36 2002-10-24 14:50:37 2002-10-24 14:50:38 2002-10-24 14:50:39 2002-10-24 14:50:40 show status like "created_tmp%tables"; Variable_name Value Created_tmp_disk_tables 0 Created_tmp_tables 2 drop table t1;