How to create trigger for broken cars using IF statement

Question

I want to create a trigger that will not allow to rent a car if it is currently being repaired. Im quite new in triggers... could anyone shed some light on this aspect of trigge

Answer 1

I didn't tested it so it might have a missing condition or something like that. But it should help you on the correct path

Query

DELIMITER $$
CREATE TRIGGER `check_repair` BEFORE INSERT ON `bookings` FOR EACH ROW BEGIN 
    # We need to save the "count"
    DECLARE inspections_count INT DEFAULT 0;

    # Check if where is a repair going which matches the vehicle_id
    SELECT
      1 INTO inspections_count # store the "count" into the variable.
    FROM inspections
    WHERE
        inspections.vehicle_id = NEW.vehicle_id
      AND
        repair_complete = 'No'
    ORDER BY 
     inspections.start_date DESC
   LIMIT 1;

    # if there is a "count" stop the insert.
    IF inspections_count = 0 THEN 
      SIGNAL SQLSTATE '45000'
      SET MESSAGE_TEXT = 'vehicle is in repair';
    END IF;
END
$$
DELIMITER ;