在删除它之前获取字段值

Question

我有两个表格类别（层次结构）和具有关系的附件。

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

我想从这些类别相关的附件中删除！

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 and Foreign key constraints上使用FOREIGH KEYS，并为与类别和附件表相关的键定义ON DELETE - CASCADE选项。

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