Well, at the risk of sounding rude, it's simply not possible to get fewer than all rows from Table A in the query you posted (and I re-posted, with the insignificant modification of leaving out a redundant ISNULL()). By definition, SELECT . . . FROM TableA LEFT OUTER JOIN TableB will return all rows from TableA and join to them the rows from TableB that satisfy the join condition(s). Some rows from TableA may be joined to one or many rows from TableB and some may be joined to zero rows from TableB, but ALL rows from TableA will appear in the result. There MUST be some other code at work here.