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
http://www.nowcoder.com/practice/ce313253a81c4947b20e801cd4da7894
select Orders.cust_id,sum(item_price * quantity) total_ordered from OrderItems right join Orders on OrderItems.order_num = Orders.order_num group by cust_id order by total_ordered desc
因为是按照总金额的大小进行排序,所以对于消费的总金额用sum 函数,然后分组依据为客户的id