เที่ยวบินจากแนชวิลล์ไปคลีฟแลนด์ไม่จำเป็นต้องใช้ตารางทั้งหมด
flight from NASHVILLE to CLEVELANDIt is not neccessary to use all the tables.
 aircraft:  aircraft_code [ varchar]  aircraft_description [ varchar]  manufacturer [ varchar]  basic_type [ varchar]  engines [ int]  propulsion [ varchar]  wide_body [ varchar]  wing_span [ int]  length [ int]  weight [ int]  capacity [ int]  pay_load [ int]  cruising_speed [ int]  range_miles [ int]  pressurized [ varchar] 
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 = 'NASHVILLE' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'CLEVELAND' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code