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Columns that Contain a Null Value By Default

  • Článek

By default, a null value in a column maps to the absence of the attribute, node, or element. This default behavior can be overwritten by requesting element-centric XML using the ELEMENTS directive and specifying XSINIL to request adding elements for NULL values, as shown in the following query:

SELECT EmployeeID as "@EmpID",   
       FirstName  as "EmpName/First",   
       MiddleName as "EmpName/Middle",   
       LastName   as "EmpName/Last"  
FROM   HumanResources.Employee E, Person.Contact C  
WHERE  E.EmployeeID = C.ContactID  
AND    E.EmployeeID=1  
FOR XML PATH, ELEMENTS XSINIL

The following shows the result. Note that if XSINIL is not specified, the <Middle> element will be absent.

<row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" EmpID="1">  
  <EmpName>  
    <First>Gustavo</First>  
    <Middle xsi:nil="true" />  
    <Last>Achong</Last>  
  </EmpName>  
</row>

See Also

Use PATH Mode with FOR XML