从id不匹配的多个表中删除

Question

我有大约10个表，如： 城市，地区，城镇等都有school_id专栏。

我想删除school_id中与学校表相比没有匹配的所有表中的school_id。我可以轻松地为一张桌子做这件事。像这样：

DELETE FROM cities
 WHERE school_id NOT IN (SELECT s.id 
                        FROM schools s)

对于地区表：

DELETE FROM districts
 WHERE school_id NOT IN (SELECT s.id 
                        FROM schools s)

我的问题是有没有办法将所有这些查询合二为一？

Answer 1

您可以使用简单的JOIN

执行此操作

delete a, b from cities a
join districts b using(school_id)
where school_id not in (select id from schools)

为要删除的每个表添加join。

delete a, b, c from cities a
join districts b using(school_id)
join tables3 c using(school_id)
where school_id not in (select id from schools)