题解 | #返回每个顾客不同订单的总金额#

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