ค้นหาเที่ยวบินที่ออกจากฟิลาเดลเฟียและมาถึงดัลลาสภายในเวลา 12.00 น. ไม่จำเป็นต้องใช้ตารางทั้งหมด
find the flights that leave PHILADELPHIA and arrive in DALLAS by 1200It is not neccessary to use all the tables.
 class_of_service:  booking_class [ varchar]  rank [ int]  class_description [ text] 
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_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'DALLAS' AND flight.arrival_time <= 1200 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