DELIMITER $$
CREATE OR REPLACE DEFINER=`vn`@`localhost` TRIGGER `vn`.`expeditionPallet_beforeInsert`
	BEFORE INSERT ON `expeditionPallet`
	FOR EACH ROW
BEGIN

	DECLARE vNewPosition INT;
    
	SELECT MAX(position) + 1 INTO vNewPosition
		FROM vn.expeditionPallet
        WHERE truckFk = NEW.truckFk;
   
	SET NEW.position = IFNULL(vNewPosition,1);
    
END$$
DELIMITER ;