In a query of related tables in a one to many relationship of parent to daughter table. Some parent records will have many daughter table records others will not. How would I formulate a query which can do the following. I want to find out how many patients in the parent table have only 1 record in the daughter table with a certain value. Example: How many patients ONLY had ASD in the daughter table record as opposed to 2 records one with ASD and the next with VSD? I don't want to do this in SQL. Thanks