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; 

我想从与这些类别相关的附件中删除！

我应该怎么办？

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 和外国中使用 FOREIGH KEYS键约束并为关联类别和附件表的键定义 ON DELETE - CASCADE 选项。

第二个只是从附件中删除，其中category_id BETWEEN @left AND @right;