I have a table from which I need to select all persons that have a first name that is not unique and that that set should be selected only if among the persons with a similar first name, all have a different last name. Example: FirstN LastN Bill Clinton Bill Cosby Bill Maher Elvis Presley Elvis Presley Largo Winch I want to obtain FirstN LastN Bill Clinton or FirstN LastN Bill Clinton Bill Cosby Bill Maher I tried this but it does not return what I want. SELECT * FROM Ids GROUP BY FirstN, LastN HAVING (COUNT(FirstN)>1 AND COUNT(LastN)=1)) [Edited my post after Aleandre P. Lavasseur remark]