mysql - 为什么我的子查询返回超过 1 行

Question

我想要未显示的行，但出现错误子查询返回超过 1 行

这很好用；

SELECT CONCAT( P.LastName, ', ', P.FirstName ) AS Name, 
(
SELECT MP.MembershipID
FROM membershipperson MP
WHERE MP.PersonID = P.PersonID
) 
AS MembershipID, PersonID
FROM `person` P

当我添加 ORDER BY 'MembershipID' 时，此操作会失败；如果我 ORDER BY 'PersonID'，则此操作会失败；

SELECT CONCAT( P.LastName, ', ', P.FirstName ) AS Name, 
(
SELECT MP.MembershipID
FROM membershipperson MP
WHERE MP.PersonID = P.PersonID
) 
AS MembershipID, PersonID
FROM `person` P
ORDER BY `MembershipID` ASC 

如何获取包含所有 MembershipID 行的列表？

Answer 1

您可能应该使用内部联接。像这样的事情:

SELECT CONCAT( P.LastName, ', ', P.FirstName ) AS Name, MP.MembershipID AS MembershipID, PersonID
FROM person P, membershipperson MP
WHERE MP.PersonID = P.PersonID