drop table if exists t1,t2,t3;
create table t1(id1 int not null auto_increment primary key, t char(12));
create table t2(id2 int not null, t char(12));
create table t3(id3 int not null, t char(12), index(id3));
select count(*) from t1 where id1 > 95;
count(*)
5
select count(*) from t2 where id2 > 95;
count(*)
25
select count(*) from t3 where id3 > 95;
count(*)
250
update t1,t2,t3 set t1.t="aaa", t2.t="bbb", t3.t="cc" where  t1.id1 = t2.id2 and t2.id2 = t3.id3  and t1.id1 > 90;
select count(*) from t1 where t = "aaa";
count(*)
10
select count(*) from t1 where id1 > 90;
count(*)
10
select count(*) from t2 where t = "bbb";
count(*)
10
select count(*) from t2 where id2 > 90;
count(*)
50
select count(*) from t3 where t = "cc";
count(*)
500
select count(*) from t3 where id3 > 90;
count(*)
500
delete t1.*, t2.*, t3.*  from t1,t2,t3 where t1.id1 = t2.id2 and t2.id2 = t3.id3  and t1.id1 > 95;
check table t1, t2, t3;
Table	Op	Msg_type	Msg_text
test.t1	check	status	OK
test.t2	check	status	OK
test.t3	check	status	OK
select count(*) from t1 where id1 > 95;
count(*)
0
select count(*) from t2 where id2 > 95;
count(*)
0
select count(*) from t3 where id3 > 95;
count(*)
0
delete t1, t2, t3  from t1,t2,t3 where t1.id1 = t2.id2 and t2.id2 = t3.id3  and t1.id1 > 5;
select count(*) from t1 where id1 > 5;
count(*)
0
select count(*) from t2 where id2 > 5;
count(*)
0
select count(*) from t3 where id3 > 5;
count(*)
0
delete from t1, t2, t3  using t1,t2,t3 where t1.id1 = t2.id2 and t2.id2 = t3.id3  and t1.id1 > 0;
select count(*) from t1 where id1;
count(*)
0
select count(*) from t2 where id2;
count(*)
0
select count(*) from t3 where id3;
count(*)
0
drop table t1,t2,t3;
create table t1(id1 int not null  primary key, t varchar(100)) pack_keys = 1;
create table t2(id2 int not null, t varchar(100), index(id2)) pack_keys = 1;
delete t1  from t1,t2 where t1.id1 = t2.id2 and t1.id1 > 500;
drop table t1,t2;