删除前获取字段值

Question

我有两个表类别(层次结构)和附件，它们之间有关系。

delete  from category where lft between @left and @right; 

和我想从附件中删除，这是由这些类别相关的!

我该怎么办?

Answer 1

尝试:

delete c,a category c 
 join attachment a on c.id=a.category_id 
 where c.lft between @left and @right

Answer 2

我建议在InnoDB MySQl和外键约束下使用Foreign key，并为关联类别和附件表的键定义ON DELETE - CASCADE选项。

第二个就是DELETE FROM attachments WHERE category_id BETWEEEN @left AND @right;