instruction: what is the least expensive BUSINESS class flight between ATLANTA and DALLAS
response: 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, fare AS FARE_0, fare AS FARE_1, fare_basis, flight, flight_fare AS FLIGHT_FARE_0, flight_fare AS FLIGHT_FARE_1 WHERE ((CITY_0.city_code = AIRPORT_SERVICE_0.city_code AND CITY_0.city_name = 'ATLANTA' AND CITY_1.city_code = AIRPORT_SERVICE_1.city_code AND CITY_1.city_name = 'DALLAS' AND flight.from_airport = AIRPORT_SERVICE_0.airport_code AND flight.to_airport = AIRPORT_SERVICE_1.airport_code) AND fare_basis.class_type = 'BUSINESS' AND FARE_1.fare_basis_code = fare_basis.fare_basis_code AND FLIGHT_FARE_1.fare_id = FARE_1.fare_id AND flight.flight_id = FLIGHT_FARE_1.flight_id) AND FARE_0.one_direction_cost = (SELECT MIN(FAREalias2.one_direction_cost) FROM airport_service AS AIRPORT_SERVICEalias2, airport_service AS AIRPORT_SERVICEalias3, city AS CITYalias2, city AS CITYalias3, fare AS FAREalias2, fare AS FAREalias3, fare_basis AS FARE_BASISalias1, flight AS FLIGHTalias1, flight_fare AS FLIGHT_FAREalias2, flight_fare AS FLIGHT_FAREalias3 WHERE CITYalias2.city_code = AIRPORT_SERVICEalias2.city_code AND CITYalias2.city_name = 'ATLANTA' AND CITYalias3.city_code = AIRPORT_SERVICEalias3.city_code AND CITYalias3.city_name = 'DALLAS' AND FARE_BASISalias1.class_type = 'BUSINESS' AND FAREalias3.fare_basis_code = FARE_BASISalias1.fare_basis_code AND FLIGHT_FAREalias2.fare_id = FAREalias2.fare_id AND FLIGHT_FAREalias3.fare_id = FAREalias3.fare_id AND FLIGHTalias1.flight_id = FLIGHT_FAREalias2.flight_id AND FLIGHTalias1.flight_id = FLIGHT_FAREalias3.flight_id AND FLIGHTalias1.from_airport = AIRPORT_SERVICEalias2.airport_code AND FLIGHTalias1.to_airport = AIRPORT_SERVICEalias3.airport_code) AND FLIGHT_FARE_0.fare_id = FARE_0.fare_id AND flight.flight_id = FLIGHT_FARE_0.flight_id