如何在tsql中查询xml列

Question

我有一个表,T1,在SQL Server 2008上有一个XML列,EventXML.我想查询某些节点包含特定值的所有行.更好,我想在不同的节点中检索值.表T1:

T1:
   EventID, int
   EventTime, datetime
   EventXML, XML

这是一个示例XML层次结构:

<Event>
   <Indicator>
      <Name>GDP</Name>
   </Indicator>
   <Announcement>
      <Value>2.0</Value>
      <Date>2012-01-01</Date>
   </Announcement>
</Event>

1. 如何查找与"GDP"指标相关的所有行;
2. 如何获得"GDP"指标的所有值;

Answer 1

这个怎么样？

SELECT 
    EventID, EventTime,
    AnnouncementValue = t1.EventXML.value('(/Event/Announcement/Value)[1]', 'decimal(10,2)'),
    AnnouncementDate = t1.EventXML.value('(/Event/Announcement/Date)[1]', 'date')
FROM
    dbo.T1
WHERE
    t1.EventXML.exist('/Event/Indicator/Name[text() = "GDP"]') = 1

它将找到/Event/Indicator/Name等于的所有行,GDP然后它将显示那些行<Announcement>/<Value>和<Announcement>/<Date>那些行.

请参阅SQLFiddle演示

Answer 2

DECLARE @t XML = '
<Event>
   <Indicator>
      <Name>GDP</Name>
   </Indicator>
   <Announcement>
      <Value>2.0</Value>
      <Date>2012-01-01</Date>
   </Announcement>
</Event>
<Event>
   <Indicator>
      <Name>Other</Name>
   </Indicator>
   <Announcement>
      <Value>3.0</Value>
      <Date>2012-01-01</Date>
   </Announcement>
</Event>
'

SELECT  node.value('.', 'NUMERIC(20, 2)')
FROM    @t.nodes('/Event[Indicator/Name/node()=''GDP'']/Announcement/Value') t(node)