题解 | 统计各等级会员用户下订单总额

SELECT
    t.vip,
    CASE WHEN t.order_total IS NOT NULL THEN t.order_total
    ELSE 0 
    END AS order_total
FROM (
    SELECT 
        vip,
        SUM(order_price) AS order_total
    FROM order_tb right JOIN uservip_tb
    ON order_tb.user_id = uservip_tb.user_id
    GROUP BY vip
    ORDER BY order_total DESC) t