如何将LEFT JOIN限制为SQL Server中的第一个结果？

数据库本身是旧的,有一些完整性问题.我的问题是数据库中每个电话号码应该只有1种,但情况并非如此.当我运行它时,如果每个人包含两个“Home”数字,则可以得到多行结果.

如何修改SQL以获取列出的第一个电话号码,并忽略其余的号码？我在SQL Server中,我知道TOP语句.但是,如果我将“TOP 1”添加到LEFT JOIN select语句中,那么它只会给出数据库中的第一个条目,而不是每个用户的第一个条目.

这是针对SQL Server 2000.

谢谢,

SELECT  Users.UserID,Users.FirstName,Users.LastName,HomePhone,WorkPhone,FaxNumber

FROM Users

LEFT JOIN
 (SELECT UserID,PhoneNumber AS HomePhone
 FROM UserPhoneNumbers LEFT JOIN UserPhoneNumberTypes ON UserPhoneNumbers.UserPhoneNumberTypeID=UserPhoneNumberTypes.UserPhoneNumberTypeID
 WHERE UserPhoneNumberTypes.PhoneNumberType='Home') AS tmpHomePhone
 ON tmpHomePhone.UserID = Users.UserID
LEFT JOIN
 (SELECT UserID,PhoneNumber AS WorkPhone
 FROM UserPhoneNumbers LEFT JOIN UserPhoneNumberTypes ON UserPhoneNumbers.UserPhoneNumberTypeID=UserPhoneNumberTypes.UserPhoneNumberTypeID
 WHERE UserPhoneNumberTypes.PhoneNumberType='Work') AS tmpWorkPhone
 ON tmpWorkPhone.UserID = Users.UserID
LEFT JOIN
 (SELECT UserID,PhoneNumber AS FaxNumber
 FROM UserPhoneNumbers LEFT JOIN UserPhoneNumberTypes ON UserPhoneNumbers.UserPhoneNumberTypeID=UserPhoneNumberTypes.UserPhoneNumberTypeID
 WHERE UserPhoneNumberTypes.PhoneNumberType='Fax') AS tmpFaxNumber
 ON tmpFaxNumber.UserID = Users.UserID

解决方法

SELECT UserID,MAX(PhoneNumber) AS HomePhone FROM [...] GROUP BY UserID

如果你不在乎什么是用户的家庭号码的返回…

（编辑：李大同）

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