题解 | #返回每个顾客不同订单的总金额#

select cust_id,sum(item_price*quantity) total_ordered  from(
  select
	  OrderItems.order_num as OIon,
	  item_price,
	  quantity,
	  cust_id
  from
	  OrderItems,
	  Orders
  where
	  OrderItems.order_num = Orders.order_num) temp
group by cust_id

order by total_ordered desc