带字符串的SQL Pivot

Question

我在SQL Server中有两个表：客户和地址

客户表 ：

CustomerID  FirstName  LastName
----------- ---------- ----------
1           Andrew     Jackson         
2           George     Washington

地址表 ：

AddressID   CustomerID  AddressType City
----------- ----------- ----------- ----------
1           1           Home        Waxhaw     
2           1           Office      Nashville    
3           2           Home        Philadelphia

这是我需要的输出：

CustomerID  Firstname  HomeCity      OfficeCity
----------- ---------- ----------    ----------
1           Andrew     Waxhaw        Nashville
2           George     Philadelphia  Null

这是我的查询，但没有得到正确的结果：

SELECT CustomerID, Firstname, HOme as HomeCity, Office as OfficeCity FROM 
   (SELECT C.CustomerID, C.FirstName, A.AddressID, A.AddressType, A.City 
    FROM Customer C, Address A 
    WHERE C.CustomerID = A.CustomerID)as P
PIVOT (MAX(city) FOR AddressType in ([Home],[Office])) as  PVT

这是我得到的结果：

CustomerID  Firstname  HomeCity      OfficeCity
----------- ---------- ----------    ----------
1           Andrew     Waxhaw        NULL
1           Andrew     NULL          Nashville
2           George     Philadelphia  Null

如您所见，客户1在最终结果中出现了两次。每个客户只能获得一行吗？

我查看了这个示例，但没有帮助：http：//stackoverflow.com/questions/6267660/sql-query-to-
convert-rows-into-columns

谢谢

Answer 1

之所以会显示此行，是因为您AddressID在子查询“
P”的选择列表中。因此，即使您没有顶级的AddressID，也要按此PIVOT功能对它进行分组。您需要将其更改为：

SELECT  CustomerID, Firstname, Home as HomeCity, Office as OfficeCity 
FROM    (   SELECT C.CustomerID, C.FirstName, A.AddressType, A.City 
            FROM #Customer C, #Address A 
            WHERE C.CustomerID = A.CustomerID
        ) AS P
        PIVOT 
        (   MAX(city) 
            FOR AddressType in ([Home],[Office])
        ) AS  PVT

尽管我倾向于INNER JOIN在客户和地址之间使用显式联接而不是隐式联接。