How many rooms in total are there in the apartments in the building with short name "Columbus Square"?
SELECT sum(T2.room_count) FROM Apartment_Buildings AS T1 JOIN Apartments AS T2 ON T1.building_id  =  T2.building_id WHERE T1.building_short_name  =  "Columbus Square"
total rooms in apartments = SUM(T2.room_count); in the building with short name \"Columbus Square\" refers to T1.building_short_name = \"Columbus Square\";