select c.cust_name, o1.order_num, (o2.quantity*o2.item_price) as OrderTotal from Orders o1 left join Customers c on c.cust_id = o1.cust_id left join OrderItems o2 on o1.order_num = o2.order_num order by cust_name,order_num asc; 一种三表联合查询的方式。