4 курс 1 семестр / Курсовая / SQL / PR7

DELIMITER $$
CREATE PROCEDURE `pr7`(IN flight_id INT, IN book_date DATE)
BEGIN
SELECT planes.seats - COUNT(tikets.seat) as available_seats
FROM planes
JOIN flights ON planes.plane_id = flights.plane_id
LEFT JOIN tikets ON flights.flight_id = tikets.flight_id
WHERE flights.flight_id = flight_id AND tikets.book_date = book_date
GROUP BY flights.flight_id;

IF NOT EXISTS (SELECT * FROM flights WHERE flights.flight_id = flight_id) THEN
SELECT 'Не найдено ни одного рейса с таким идентификатором' as 'Error';
ELSEIF NOT EXISTS (SELECT * FROM tikets WHERE tikets.book_date = book_date) THEN
SELECT 'Билеты на эту дату не найдены' as 'Error';
END IF;

END $$
DELIMITER ;

CALL pr7(32, '2022-10-01');