2
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
5
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
7
3
create table t1(a int auto_increment, primary key(a));
8
4
create table t2(b int auto_increment, c int, primary key(b));
9
5
insert into t1 values (1),(2),(3);