select @id := id from tb_user where id = 3;
delete from tb_user where id = @id;
这句可以删除表tb_user的id=3的记录
select @id := 5;
delete from tb_user where id = @id;
这句可以删除表tb_user的id=5的记录
select * from tb_user
select @id := id from tb_user where id = 3;
delete from tb_user where id = @id;
这句可以删除表tb_user的id=3的记录
select @id := 5;
delete from tb_user where id = @id;
这句可以删除表tb_user的id=5的记录
select * from tb_user