แสดงค่าโดยสารไปกลับจากลาสเวกัสไปยังฮูสตันโดยไม่แวะพัก ไม่จำเป็นต้องใช้ตารางทั้งหมด
show me round trip fares from LAS VEGAS to HOUSTON nonstopIt is not neccessary to use all the tables.
 dual_carrier:  main_airline [ varchar]  low_flight_number [ int]  high_flight_number [ int]  dual_airline [ varchar]  service_name [ text] 
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 = 'LAS VEGAS' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'HOUSTON' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND NOT fare.round_trip_cost IS NULL AND flight_fare.fare_id = fare.fare_id AND flight.flight_id = flight_fare.flight_id AND flight.stops = 0