โปรดบอกค่าโดยสารไปกลับจากพิตส์เบิร์กไปฟิลาเดลเฟีย ไม่จำเป็นต้องใช้ตารางทั้งหมด
please give me round trip fares from PITTSBURGH to PHILADELPHIAIt is not neccessary to use all the tables.
 time_zone:  time_zone_code [ text]  time_zone_name [ text]  hours_from_gmt [ int] 
SELECT DISTINCT fare.fare_id FROM airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, city AS CITY_0, city AS CITY_1, fare, flight, flight_fare WHERE CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'PITTSBURGH' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'PHILADELPHIA' AND flight_fare.fare_id = fare.fare_id AND flight.flight_id = flight_fare.flight_id AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code