题解 | #返回每个顾客不同订单的总金额#
https://www.nowcoder.com/practice/ce313253a81c4947b20e801cd4da7894
select o.cust_id,oi.total_ordered from Orders o left join (select order_num,sum(item_price * quantity) as total_ordered from OrderItems group by order_num) oi on o.order_num = oi.order_num order by oi.total_ordered desc ;感觉非常的简单 先处理一下 子表然后跟主表关联起来就行
最再排个序