That suggests that the field value is already null. IsNull () would return false for an empty string.<BR><BR>SQL Server provides the NullIf () function, which does what you want; depending on your ...

One of the trickiest aspects of relational database management can be dealing with missing information. The standard method of representing missing information is to set the “value” to null. A null ...

IS NULL and IS MISSING are predicates that test for a missing value. IS NULL and IS MISSING are used in the WHERE, ON, and HAVING expressions. Each predicate resolves to true if the sql-expression's ...