How to combine domain login and intranet login

You named the variable the same as the field. In the query, suburb is first sought in the scope of the query, and it matches the field suburb even though it doesn't use the pp table alias.

So you're actually comparing the field with itself, therefore getting all records (where suburb is NOT NULL, that is). The procedure parameter isn't used in the query at all.

The solution: change the name of the procedure parameter.

To prevent errors like this, I always use P_ as a prefix for procedure/function parameters and V_ as a prefix for local variables. This way, they never mingle with field names.