Question

我需要编写一个SQL脚本，在table1中选择一条记录，然后在数据库的其余表中进行查找。如果找不到记录，我需要从table1中删除记录。有人提供一些示例脚本吗？

Answer 1

一个例子

delete table1
where not exists (select 1 
                   from Table2 
                   where table1.SomeColumn = Table2.SomeColumn)
AND table1.SomeColumn = 5 --just an example,

如果要删除表1中表2中不存在的所有行

，请保留AND

您也可以使用LEFT JOIN或NOT IN

Answer 2

我做过这样的事情：

DELETE table1
  FROM table1
 WHERE table1.ID NOT IN (
       SELECT RefID FROM Table2
       UNION
       SELECT RefID FROM Table3
       ...
       )

假设RefID是table1.ID的FK。这是你需要的吗？

Answer 3

DELETE FROM Table1 WHERE id=10 AND NOT EXISTS (SELECT * FROM Table2 WHERE id=10);

Answer 4

非常一般，（因为你提供的细节很少）

Delete Table1 t1
Where [Criteria to find table1 Record]
  And Not Exists(Select * From Table2
                 Where pk = t1.Pk)
  And Not Exists(Select * From Table3
                 Where pk = t1.Pk)
  And Not Exists(Select * From Table4
                 Where pk = t1.Pk)
  ... etc. for all other tables

SQL删除查询

4 个答案: