DELIMITER //
CREATE PROCEDURE ledigabilar(startpoint DATE, endpoint DATE)
  BEGIN

    SELECT DISTINCT CarNumber FROM Bookings WHERE NOT ((Bookings.StartDate BETWEEN startpoint AND endpoint)
    OR (Bookings.EndDate BETWEEN startpoint AND endpoint)
   OR (Bookings.StartDate<=startpoint AND Bookings.EndDate>=endpoint));

END //


CALL ledigabilar ('2018-01-05', '2018-01-30');