是否可以从同一SQL语句中的多个表中删除？

Question

可以使用join语句删除以限定要删除的集合,例如:

DELETE J
FROM Users U
inner join LinkingTable J on U.id = J.U_id
inner join Groups G on J.G_id = G.id

WHERE G.Name = 'Whatever'
and U.Name not in ('Exclude list')

但是我有兴趣删除连接标准的两个方面 - LinkingTable记录和它所依赖的用户记录.我无法启用级联,因为我的解决方案首先是实体框架代码,而双向关系是多个级联路径.

理想情况下,我喜欢这样的东西:

DELETE J, U
FROM Users U
inner join LinkingTable J on U.id = J.U_id
...

从句法上来说这没有用,但我很好奇这样的事情是否可行？

Answer 1

不,你需要运行多个语句.

因为您需要从两个表中删除,所以请考虑创建匹配ID的临时表:

SELECT U.Id INTO #RecordsToDelete
FROM Users U
   JOIN LinkingTable J ON U.Id = J.U_Id
...

然后从每个表中删除:

DELETE FROM Users 
WHERE Id IN (SELECT Id FROM #RecordsToDelete)

DELETE FROM LinkingTable
WHERE Id IN (SELECT Id FROM #RecordsToDelete)