题解 | 返回每个顾客不同订单的总金额
返回每个顾客不同订单的总金额
https://www.nowcoder.com/practice/ce313253a81c4947b20e801cd4da7894
SELECT o.cust_id, -- 关联子查询：计算当前顾客的所有订单总金额 (SELECT SUM(item_price * quantity) FROM OrderItems oi -- 子查询与外层关联：只统计当前cust_id对应的订单 WHERE oi.order_num = o.order_num) AS total_ordered FROM Orders o -- 按总金额降序排序（大→小） ORDER BY total_ordered DESC;
