instruction: i'd like to get a flight from WASHINGTON to OAKLAND with a stopover in DFW for 9 15
response: SELECT DISTINCT flight.flight_id FROM airport, airport_service AS AIRPORT_SERVICE_0, airport_service AS AIRPORT_SERVICE_1, city AS CITY_0, city AS CITY_1, date_day, days, flight, flight_stop WHERE ((airport.airport_code = 'DFW' AND date_day.day_number = 15 AND date_day.month_number = 9 AND date_day.year = 1991 AND days.day_name = date_day.day_name AND flight_stop.stop_airport = airport.airport_code AND flight.flight_days = days.days_code AND flight.flight_id = flight_stop.flight_id) AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'OAKLAND' AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'WASHINGTON' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code