1
create table t1 (a int not null auto_increment primary key);
2
insert into t1 values (NULL);
3
insert into t1 values (NULL);
4
insert into t1 values (NULL);
5
insert into t1 values (NULL);
6
insert into t1 values (NULL);
7
insert into t1 values (NULL);
8
insert into t1 values (-1);
9
select last_insert_id();
12
delete from t1 where a in (2,3,4);
13
insert into t1 values (NULL);