Show the apartment numbers of apartments with unit status availability of both 0 and 1.
SELECT T1.apt_number FROM Apartments AS T1 JOIN View_Unit_Status AS T2 ON T1.apt_id  =  T2.apt_id WHERE T2.available_yn  =  0 INTERSECT SELECT T1.apt_number FROM Apartments AS T1 JOIN View_Unit_Status AS T2 ON T1.apt_id  =  T2.apt_id WHERE T2.available_yn  =  1
apartment numbers of apartments with unit status availability of both 0 and 1 refers to using INTERSECT between two SELECT statements where available_yn = 0 and available_yn = 1;