SQL Server 2008 FOR XML PATH 帮助

Question

我有一个历史记录表。 [已添加] 的一个字段具有日期时间数据类型。我要做的是选择用户 20 条最近的记录，然后按从 [add] 字段派生的字符串对它们进行分组。假设它的值为2011-05-24 03:32:57.353，字符串为'Tuesday, May 24, 2011'。我想按该字符串对记录进行分组，然后按实际时间对子节点进行排序。我还想要一些自定义 XML 输出。

<ActivityHistory>
   <Actvities foo="Tuesday, May 24, 2011">
       <Activity id="10000" bar="zoo" bam="2011-05-24 03:32:57.353" />
       <Activity id="10001" bar="zoo" bam="2011-05-24 03:31:57.353" />
       <Activity id="10002" bar="zoo" bam="2011-05-24 03:28:57.353" />
       <Activity id="10003" bar="zoo" bam="2011-05-24 03:21:57.353" />
   </Activities>
   <Actvities foo="Monday, May 23, 2011">
       <Activity id="9990" bar="zoo" bam="2011-05-23 03:32:57.353" />
       <Activity id="9989" bar="zoo" bam="2011-05-23 03:31:57.353" />
       <Activity id="9988" bar="zoo" bam="2011-05-23 03:28:57.353" />
       <Activity id="9987" bar="zoo" bam="2011-05-23 03:21:57.353" />
   </Activities>
   <Actvities foo="Sunday, May 22, 2011">
       <Activity id="9900" bar="zoo" bam="2011-05-22 03:32:57.353" />
       <Activity id="9899" bar="zoo" bam="2011-05-22 03:31:57.353" />
       <Activity id="9898" bar="zoo" bam="2011-05-22 03:28:57.353" />
       <Activity id="9897" bar="zoo" bam="2011-05-22 03:21:57.353" />
   </Activities>
</ActivityHistory>

此有效负载将始终只有 0-20 条记录。可能永远是 20。

到目前为止，我的查询看起来像这样。

    SELECT TOP 20
     fnHistoryGroupingText(Added) [@foo]        
    FROM ActivityHistory 
WHERE MricId = 1
GROUP BY fnHistoryGroupingText(Added)
FOR XML PATH ('Activities'), ROOT ('ActivityHistory')

它生成的 XML 类似于我正在寻找的内容。

<ActivityHistory>
   <Activities foo="Friday, May 20, 2011" />
   <Activities foo="Monday, May 23, 2011" />
   <Activities foo="Saturday, May 21, 2011" />
   <Activities foo="Sunday, May 22, 2011" />
   <Activities foo="Tuesday, May 24, 2011" />
</ActivityHistory>

请注意它不是按日期排序的并且缺少子节点。我希望它们按时间倒序排列。我故意从查询中排除了一些字段，因为此时在查询中我有点得到我最终想要的结构。当我介绍其他字段时，XML 就差远了。分组文本是一个 varchar，不能很好地转换为日期。我可以以某种方式使用 [add] 字段，但是当我将它包含在查询中时，它会破坏我的分组。谁能指出我正确的方向来纠正这些问题？ [A] 正确编写查询，[B] 告诉我如何正确输出我正在寻找的 XML。

Answer 1

试试这个：

/*  INIT  */
DECLARE @ActivityHistory TABLE (id int, bar VARCHAR(3), bam datetime)
INSERT INTO @ActivityHistory 
             SELECT  id='10000', bar='zoo', bam='2011-05-24 03:32:57' 
       UNION SELECT  id='10001', bar='zoo', bam='2011-05-24 03:31:57' 
       UNION SELECT  id='10002', bar='zoo', bam='2011-05-24 03:28:57' 
       UNION SELECT  id='10003', bar='zoo', bam='2011-05-24 03:21:57' 
       UNION SELECT  id= '9990', bar='zoo', bam='2011-05-23 03:32:57' 
       UNION SELECT  id= '9989', bar='zoo', bam='2011-05-23 03:31:57' 
       UNION SELECT  id= '9988', bar='zoo', bam='2011-05-23 03:28:57' 
       UNION SELECT  id= '9987', bar='zoo', bam='2011-05-23 03:21:57' 
       UNION SELECT  id= '9900', bar='zoo', bam='2011-05-22 03:32:57' 
       UNION SELECT  id= '9899', bar='zoo', bam='2011-05-22 03:31:57' 
       UNION SELECT  id= '9898', bar='zoo', bam='2011-05-22 03:28:57' 
       UNION SELECT  id= '9897', bar='zoo', bam='2011-05-22 03:21:57' 

/*  QUERY  */
;WITH 
resALL AS ( SELECT *
      , foo = DATENAME(weekday, bam)+', '+ CONVERT(VARCHAR(30), bam, 107) 
      , food = CONVERT(VARCHAR(10), bam, 121) 
    FROM @ActivityHistory AS Activity
  )
, resD AS ( SELECT DISTINCT foo, food FROM resALL 
  )

SELECT 
 Activities.foo
 , (
    SELECT id, bar, bam 
    FROM resALL AS Activity 
    WHERE foo = Activities.foo 
    ORDER BY bam desc 
    FOR XML AUTO, TYPE
   )
FROM resD AS Activities
ORDER BY Activities.food DESC
FOR XML AUTO, TYPE, ROOT ('ActivityHistory')

/*  OUTPUT
<ActivityHistory>
  <Activities foo="Tuesday, May 24, 2011">
    <Activity id="10000" bar="zoo" bam="2011-05-24T03:32:57" />
    <Activity id="10001" bar="zoo" bam="2011-05-24T03:31:57" />
    <Activity id="10002" bar="zoo" bam="2011-05-24T03:28:57" />
    <Activity id="10003" bar="zoo" bam="2011-05-24T03:21:57" />
  </Activities>
  <Activities foo="Monday, May 23, 2011">
    <Activity id="9990" bar="zoo" bam="2011-05-23T03:32:57" />
    <Activity id="9989" bar="zoo" bam="2011-05-23T03:31:57" />
    <Activity id="9988" bar="zoo" bam="2011-05-23T03:28:57" />
    <Activity id="9987" bar="zoo" bam="2011-05-23T03:21:57" />
  </Activities>
  <Activities foo="Sunday, May 22, 2011">
    <Activity id="9900" bar="zoo" bam="2011-05-22T03:32:57" />
    <Activity id="9899" bar="zoo" bam="2011-05-22T03:31:57" />
    <Activity id="9898" bar="zoo" bam="2011-05-22T03:28:57" />
    <Activity id="9897" bar="zoo" bam="2011-05-22T03:21:57" />
  </Activities>
</ActivityHistory>
*/