SELECT COALESCE(driver_id, '总体') AS driver_id,
    ROUND(AVG(grade), 1) AS avg_grade
FROM tb_get_car_order
WHERE driver_id IN (
    SELECT driver_id FROM tb_get_car_order
    WHERE DATE_FORMAT(order_time, '%Y%m') = '202110'
        AND ISNULL(fare)
) AND NOT ISNULL(grade)
GROUP BY driver_id
WITH ROLLUP