如何使用 FOR XML 查询将 SQL Server 2005/2008 列作为相同的子节点返回？

Question

基本上，我需要以以下 XML 格式从 SQL Server 表返回一些数据：

<querydata>
  <entity name="Person.Contact">
    <row>
      <field name="FirstName">Gustavo</field>
      <field name="LastName">Achong</field>
    </row>
    <row>
      <field name="FirstName">Catherine</field>
      <field name="LastName">Abel</field>
    </row>
...
  </entity>
</querydata>

我已经提出了以下 SQL 语句：

select 'Person.Contact' as "@name", 
(select FirstName, LastName from Person.Contact for XML path('row'), TYPE)
for XML path('entity'), root('querydata')

产生以下输出：

<querydata>
  <entity name="Person.Contact">
    <row>
      <FirstName>Gustavo</FirstName>
      <LastName>Achong</LastName>
    </row>
    <row>
      <FirstName>Catherine</FirstName>
      <LastName>Abel</LastName>
    </row>
....
  </entity>
</querydata>

但我没有进一步了解。谢谢！

Answer 1

您需要取消数据透视。

尝试使用以下子查询：

SELECT 'FirstName' as [@name], FirstName as [*]
union all
SELECT 'LastName' as [@name], LastName as [*]
for xml path('field')

或者类似的东西...

我没有SQL（今天在我的iPhone上），但我在考虑：

select 'Person.Contact' as "@name", 
(select (SELECT 'FirstName' as [@name], FirstName as [*]
union all
SELECT 'LastName' as [@name], LastName as [*]
for xml path('field')) from Person.Contact for XML path('row'), TYPE)
for XML path('entity'), root('querydata')

Answer 2

非常感谢罗布！你绝对让我走上了正确的道路，为你+1！我必须将所有内容包装在 SELECT * FROM 语句中，否则 SQL 服务器会抱怨。这是最终的工作查询：

SELECT 'Person.Contact' as "@name",
(SELECT 
    (SELECT * from (SELECT 'FirstName' as [@name], [FirstName] as [*]
    union all
    SELECT 'LastName' as [@name], [LastName] as [*]) y
    for xml path('field'), TYPE)
from Person.Contact for XML path, TYPE)
for XML path('entity'), root('querydata')