题解 | #返回顾客名称和相关订单号以及每个订单的总价#

SELECT
    c.cust_name,
    o.order_num,
    (
        SELECT
            SUM(item_price*quantity)
        FROM
            OrderItems os
        WHERE
            os.order_num = o.order_num
    ) AS OrderTotal
FROM
    Customers c
    LEFT JOIN Orders o ON o.cust_id = c.cust_id
ORDER BY
    c.cust_name,
    o.order_num;