ASA Database Administration Guide
  Database Options
    Alphabetical list of options

FOR_XML_NULL_TREATMENT option [database]

Function 

Controls the treatment of NULL values in queries that use the FOR XML clause.

Allowed values 

EMPTY, OMIT

Default 

OMIT

See also 

Using the FOR XML clause to retrieve query results as XML

SELECT statement

Description 

If you execute a query that includes the FOR XML clause, the FOR_XML_NULL_TREATMENT option determines how NULL values are treated. By default, elements and attributes that contain NULL values are omitted from the result. Setting this option to EMPTY generates empty elements or attributes if the value is NULL.