delete from A where a_id in (select id from B where b_id in (select id from C where c_id = ?))

题目

delete from A where a_id in (select id from B where b_id in (select id from C where c_id = ?))
请问这句SQL语句怎么优化? 我的意思万一in语句里面的内容过多会出问题的,怎么用连接表的形式去delete?

答案

IN中的数据量不能大于2K条,否则会报错
先使用SELECT语句将数据查询到一张临时表
然后使用INNER JOIN进行内联删除