BEGIN
WHILE (@q > 0) DO

IF (maintainStock = 1) THEN
    SET @date1 = (SELECT MIN(expiry_date) FROM `stock_current` WHERE closing > 0);
    UPDATE `stock_current` SET sold = sold + 1, closing = closing - 1 WHERE item_id = iid AND expiry_date = @date1;
    SET qqty = qqty - 1;

ELSE
    SET @date2 = (SELECT MIN(expiry_date) FROM `stock_current`);
    UPDATE `stock_current` SET sold = sold + 1 WHERE item_id = iid AND expiry_date = @date2;
    SET qqty = qqty - 1;

END IF;
END WHILE;
END