当第二个是返回多个值的子选择时，如何进行比较？

Question

这是我的SQL语句：

SELECT DISTINCT a.* 
   FROM OWU_Nomination as a, 
        Merchants as b WHERE a.CallFlag = 'False' 
   AND a.nominatedDate < DateAdd(hour, -24, getdate()) 
   AND a.email != (SELECT c.Email from Members as c where c.MemberID = b.MemberID)

这里的问题是a.email !=之后的子选择返回多个记录。我想看看a.email是否在从子选择返回的任何电子邮件中，这可能吗？是否有包含功能或类似的东西会这样做？

Answer 1

根据你的问题，我不确定你是否希望它在集合中或不在集合中。

如果必须在集合中，请使用以下句子：

AND a.email IN (SELECT c.Email from Members as c where c.MemberID = b.MemberID)

否则：

AND a.email NOT IN (SELECT c.Email from Members as c where c.MemberID = b.MemberID)