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 overridden by using the ELEMENTS XSINIL keyword phrase. This phrase requests element-centric XML. This means that null values are explicitly indicated in the returned results. These elements will have no value.
The ELEMENTS XSINIL phrase is shown in the following Transact-SQL SELECT example.
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>