ตัวเมืองจากสนามบินในดัลลาซีอยู่ไกลแค่ไหนไม่จำเป็นต้องใช้โต๊ะทั้งหมด
how far is downtown from the airport in DALLASIt is not neccessary to use all the tables.
 flight_leg:  flight_id [ int]  leg_number [ int]  leg_flight [ int] 
SELECT DISTINCT AIRPORT_SERVICE_0.miles_distant FROM airport, airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, city AS CITY_0, city AS CITY_1 WHERE airport.airport_code = AIRPORT_SERVICE_0.airport_code AND airport.airport_code = AIRPORT_SERVICE_1.airport_code AND CITY_0.city_code = AIRPORT_SERVICE_1.city_code AND CITY_0.city_name = 'DALLAS' AND CITY_1.city_code = AIRPORT_SERVICE_0.city_code AND CITY_1.city_name = 'DALLAS'