เที่ยวบินตรงจากซีแอตเทิลไปเดนเวอร์ไม่จำเป็นต้องใช้ตารางทั้งหมด
nonstop flights from SEATTLE to DENVERIt is not neccessary to use all the tables.
 airline:  airline_code [ varchar]  airline_name [ text]  note [ text] 
SELECT DISTINCT flight.flight_id FROM airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, city AS CITY_0, city AS CITY_1, flight WHERE (CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'SEATTLE' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'DENVER' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND flight.stops = 0