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
解题思路：
1. 使用表别名，OrderItems AS a, Orders AS b
2. 判断条件为a.order_num = b.order_num
3. 有同一顾客下的不同订单，因此需要用到GROUP BY
select cust_id, sum(quantity*item_price) AS total_ordered from OrderItems AS a, Orders AS b where a.order_num = b.order_num group by cust_id order by sum(item_price*quantity) desc;
投递快手等公司10个岗位