>DECLARE @IdList varchar(8000) >SELECT @IdList = ISNULL(@IdList + ', ', '') + StudentId > FROM survey > WHERE StudentId IN ( SELECT StudentId FROM survey > WHERE interest IN (3,45) > GROUP BY StudentId > HAVING COUNT(*) = 2 ) >GROUP BY StudentId >SELECT @IdListAs you can see, ther are two "variables" in this query: the list of interests '(3,45)' and number of valuses in the list - '2'.