Is there a way to create a rule with a where clause that will allow entry to made into the table if the value exists in another table or if the value is null?
I thought it would be something like this: WHERE EXISTS (SELECT Column1 FROM Table1 WHERE Table1.Column1 = Table2.Column2 ) or Table2.Column2 is null but that where clause is not working. Is possible to just store a null value in the lookup table or should I just set a default value in the primary table? Thanks, Charlie
