IsNull(v)
Returns a value that indicates if a variant contains the NULL value.
The parameter v can be any variant. IsNull returns a TRUE if v contains NULL. If isNull returns a FALSE the variant expression is not NULL.
The NULL value is special because it indicates that the v parameter contains no data. This is different from a null-string, which is a zero length string and an empty string which has not yet been initialized.
Related Topics: IsDate, IsEmpty, IsNumeric, VarType