ข้อมูลเกี่ยวกับเที่ยวบินจากพิตส์เบิร์กไปซานฟรานซิสโกไม่จำเป็นต้องใช้ตารางทั้งหมด
information on flights from PITTSBURGH to SAN FRANCISCOIt is not neccessary to use all the tables.
 restriction:  restriction_code [ text]  advance_purchase [ int]  stopovers [ text]  saturday_stay_required [ text]  minimum_stay [ int]  maximum_stay [ int]  application [ text]  no_discounts [ 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_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 = 'SAN FRANCISCO' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code