Use this Microsoft System Center Configuration Manager 2007 dialog box to compare a query attribute with a null value.
Any data type can have a null value, and null values are unknown. Therefore, they are not evaluated as True or False. Dealing with null values requires using three-valued logic (True, False, and Unknown). For example, the expression USER ="ChrisJones" is evaluated as either True or False, unless USER is null, in which case the expression is evaluated as Unknown. For more information, see the SQL Server documentation.
The attribute class, optional alias, and query attribute for the query result. Click Select to specify the query attribute and attribute class.
Specifies a query attribute and attribute class. Click to open the Select Attribute dialog box.
The relational operator for this query criterion.