Question

我的查询返回所有拨打的电话。我需要将返回的XML值分成4列：

FirstCallDate，SecondCallDate，ThirdCallDate，LastCallDate。

当前查询：

SELECT AllCalls FROM
(
SELECT  
          (  SELECT startdate
            FROM mycalls i WITH (NOLOCK) WHERE i.phone = d.phone  FOR XML AUTO)
            AS AllCalls

  FROM [MYDB].[dbo].[Accounts] d WITH (NOLOCK)   
  WHERE SubmittedDate BETWEEN @MyStartDate AND @MyEndDate

) e

有时会返回：

NULL
i startdate =“2012-02-29T13：50：37”/＆gt;
i startdate =“2012-02-29T14：20：58”/＆gt; i startdate =“2012-02-29T14：21：13”/＆gt; （删除了开始括号）
3 +日期
4 +日期
5 +日期
等

所以我的返回查询应该看起来像下面的sql，但每列只能保存1个日期。

    SELECT FirstCallDate, SecondCallDate, ThirdCallDate, LastCallDate
 FROM
    (
    SELECT  
              (  SELECT startdate
                FROM mycalls i WITH (NOLOCK) WHERE i.phone = d.phone  FOR XML AUTO)
                AS AllCalls

      FROM [MYDB].[dbo].[Accounts] d WITH (NOLOCK)   
      WHERE SubmittedDate BETWEEN @MyStartDate AND @MyEndDate

    ) e

关于如何将XML解析回SQL列的任何想法？

Answer 1

内置的XML解析器允许您将XML转换回行而不是列。您唯一可以做的就是基本上“撤消”XML聚合。请参阅SQL Server中的XML主题：http://msdn.microsoft.com/en-us/library/ms189887.aspx。这个子主题我在名称空间上用作参考：http://msdn.microsoft.com/en-us/library/ms177400.aspx。

从那里你可以随意转动结果。我已经调整了您的查询：

WITH XMLNAMESPACES ('uri' as ns1)
SELECT phone, [1] AS FirstCall, [2] As SecondCall, [3] As ThirdCall, [4] As LastCall
FROM   (SELECT RN, phone, IndexRef
        FROM   (SELECT phone, CAST((SELECT StartDate as 'ns1:StartDate'
                      FROM   mycalls i WITH (NOLOCK) WHERE i.phone = d.phone FOR XML RAW('ns1:Prod'), ELEMENTS) AS XML) AS AllCalls
                FROM   [mydb].[dbo].[Accounts] d
                WHERE  phone in (31304,35549,39794,42711,51201,52529)) ns1
               CROSS APPLY (SELECT row_number() over (order by relop.value('.','DateTime')) RN, relop.value('.','DateTime') AS CallLog 
                              FROM ns1.AllCalls.nodes( N'//ns1:StartDate') AS ro(relop)) r) X
       PIVOT(MAX(CallLog) FOR RN IN ([1],[2],[3],[4])) P

显然，对于这个查询，XML在中间只是膨胀，可以跳过。（查询跟随）。但是，如果您从直接查询以外的某些源绑定到XML输出，则此方法很有用。

不使用XML，更容易。

SELECT P.phone, p.[1] AS FirstCallDate, p.[2] AS SecondCallDate, p.[3] AS ThirdCallDate, p.[4] AS LastCallDate
FROM   (SELECT ROW_NUMBER() OVER (PARTITION BY i.phone ORDER BY i.StartDate) i.phone, CallOrder, StartDate
        FROM   [mydb].[dbo].[Accounts] d
               JOIN mycalls i ON d.phone = i.phone
        WHERE  d.SubmittedDate BETWEEN @MyStartDate AND @MyEndDate) X
       PIVOT (MAX(StartDate) FOR CallOrder IN ([1], [2], [3], [4])) P

在SQL的上下文中你无法做的是创建一个具有任意数量列的数据透视图（认为肯定会很好！）

Answer 2

您正在使用XML按帐户汇总数据。我想你完全避免使用XML并使用ROW_NUMBER（）OVER（）构造来获取每个帐户的日期范围内的最后4个调用，然后使用PIVOT运算符进行透视。

将SQL XML解析回SQL列

2 个答案: