4 курс 1 семестр / Курсовая / SQL / PR4

DELIMITER $$
CREATE PROCEDURE `pr4`(IN start_date DATE, IN end_date DATE)
BEGIN
SELECT airlines.name, COUNT(ticket_id) as tickets_sold
FROM tikets
JOIN flights ON tikets.flight_id = flights.flight_id
JOIN airlines ON flights.airline_code = airlines.airline_code
WHERE tikets.sale_date BETWEEN start_date AND end_date
GROUP BY airlines.name;

IF NOT EXISTS (SELECT * FROM tikets WHERE tikets.sale_date BETWEEN start_date AND end_date) THEN
SELECT 'Данные за этот период не найдены' as 'Error';
END IF;
END $$
DELIMITER ;

CALL pr4('2021-11-01','2021-12-01');