使用mysql执行删除语句时出现的问题

mysql执行删除sql时

1、不能有别名，例如：delete from user t where t.user_id=’?’
user表后面不能有那个t
否则报错：
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘t where t.user_id=’?” at line 1

2、where条件如果有子查询，并且是查询当前表的，需要用括号包起来当做临时表，再查一次
例如：where user_id in (select user_id from user)会执行失败，应改成
where user_id in (select user_id from (select user_id from user) as t2)
注意：当用括号包起来作为临时表时，一定要起个名字，像上面我起的名字就是t2
否则报错：
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘where user_id in (select user_id from user ) at line 1