DELIMITER //
CREATE TRIGGER Carperperson
BEFORE INSERT ON bookings
FOR EACH ROW
BEGIN
IF NEW.customer_id = bookings.customer_id
                and ((new.start_date >= bookings.start_date and new.start_date < bookings.end_date)
                        or (new.end_date > bookings.start_date and new.end_date < bookings.end_date))
THEN
SIGNAL SQLSTATE '45000' set message_text='You can only book one car per single customer a day!';


DELIMITER;