drop table if exists t1,t2;
CREATE TABLE t1 (  `id` int(11) NOT NULL default '0', `id2` int(11) NOT NULL default '0', `id3` int(11) NOT NULL default '0', `dummy1` char(30) default NULL, PRIMARY KEY  (`id`,`id2`), KEY `index_id3` (`id3`)) ENGINE=MyISAM;
insert into t1 (id,id2) values (1,1),(1,2),(1,3);
LOCK TABLE t1 WRITE;
select dummy1,count(distinct id) from t1 group by dummy1;
dummy1	count(distinct id)
NULL	1
update t1 set id=-1 where id=1;
LOCK TABLE t1 READ;
update t1 set id=1 where id=1;
ERROR HY000: Table 't1' was locked with a READ lock and can't be updated
create table t2 SELECT * from t1;
ERROR HY000: Table 't2' was not locked with LOCK TABLES
create temporary table t2 SELECT * from t1;
drop table if exists t2;
unlock tables;
create table t2 SELECT * from t1;
LOCK TABLE t1 WRITE,t2 write;
insert into t2 SELECT * from t1;
update t1 set id=1 where id=-1;
drop table t1,t2;
CREATE TABLE t1 (
index1 smallint(6) default NULL,
nr smallint(6) default NULL,
KEY index1(index1)
) ENGINE=MyISAM;
CREATE TABLE t2 (
nr smallint(6) default NULL,
name varchar(20) default NULL
) ENGINE=MyISAM;
INSERT INTO t2 VALUES (1,'item1');
INSERT INTO t2 VALUES (2,'item2');
lock tables t1 write, t2 read;
insert into t1 select 1,nr from t2 where name='item1';
insert into t1 select 2,nr from t2 where name='item2';
unlock tables;
check table t1;
Table	Op	Msg_type	Msg_text
test.t1	check	status	OK
lock tables t1 write;
check table t2;
Table	Op	Msg_type	Msg_text
test.t2	check	error	Table 't2' was not locked with LOCK TABLES
insert into t1 select nr from t1;
ERROR HY000: Table 't1' was not locked with LOCK TABLES
unlock tables;
lock tables t1 write, t1 as t1_alias read;
insert into t1 select index1,nr from t1 as t1_alias;
drop table t1,t2;