Columns that Contain a Null Value By Default

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:

USE AdventureWorks2008R2;
GO
SELECT E.BusinessEntityID as "@EmpID", 
       FirstName  as "EmpName/First", 
       MiddleName as "EmpName/Middle", 
       LastName   as "EmpName/Last"
FROM   HumanResources.Employee AS E
INNER JOIN Person.Person AS P
    ON E.BusinessEntityID = P.BusinessEntitytID
WHERE 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>Ken</First>

<Middle xsi:nil="true" />

<Last>Sánchez</Last>

</EmpName>

</row>