CREATE TABLE apartment_buildings (building_id NUMBER, building_short_name CLOB, building_full_name CLOB, building_description CLOB, building_address CLOB, building_manager CLOB, building_phone CLOB)
CREATE TABLE apartment_facilities (apt_id NUMBER, facility_code CLOB)
CREATE TABLE apartment_bookings (apt_booking_id NUMBER, apt_id NUMBER, guest_id NUMBER, booking_status_code CLOB, booking_start_date TIME, booking_end_date TIME)
CREATE TABLE apartments (apt_id NUMBER, building_id NUMBER, apt_type_code CLOB, apt_number CLOB, bathroom_count NUMBER, bedroom_count NUMBER, room_count CLOB)
CREATE TABLE view_unit_status (apt_id NUMBER, apt_booking_id NUMBER, status_date TIME, available_yn others)
CREATE TABLE guests (guest_id NUMBER, gender_code CLOB, guest_first_name CLOB, guest_last_name CLOB, date_of_birth TIME)

Find the number of apartments that have no facility.
SELECT COUNT(*) FROM apartments WHERE NOT apt_id IN (SELECT apt_id FROM apartment_facilities)
SELECT COUNT(*) FROM "apartments" WHERE NOT "apt_id" IN (SELECT "apt_id" FROM "apartment_facilities")