ฉันต้องหาเที่ยวบินจากฟิลาเดลเฟียไปซานฟรานซิสโกที่มีการแวะพักที่ดัลลาซี ไม่จำเป็นต้องใช้ตารางทั้งหมด
i need to find a flight from PHILADELPHIA to SAN FRANCISCO that has a stopover in DALLASIt is not neccessary to use all the tables.
 ground_service:  city_code [ text]  airport_code [ text]  transport_type [ text]  ground_fare [ int] 
SELECT DISTINCT flight.flight_id FROM airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, airport_service AS AIRPORT_SERVICE_2, city AS CITY_0, city AS CITY_1, city AS CITY_2, flight, flight_stop WHERE (CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'SAN FRANCISCO' AND CITY_2.city_code = AIRPORT_SERVICE_2.city_code AND CITY_2.city_name = 'DALLAS' AND flight_stop.stop_airport = AIRPORT_SERVICE_2.airport_code AND flight.flight_id = flight_stop.flight_id AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'PHILADELPHIA' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code