#where查询 select cust_name,order_num from Customers,Orders where Customers.cust_id=Orders.cust_id order by cust_name; #自然连接 select cust_name,order_num from Customers  natural join Orders order by cust_name #内连接 select cust_name,order_nu...

#子查询 select cust_id,total_order from Orders,(select order_num,sum(item_price*quantity) as total_order from OrderItems group by order_num)as tt where tt.order_num=Orders.order_num order by total_order desc #自然连接 select cust_id...

#子查询 select cust_email from Customers where cust_id in  (select cust_id from Orders where order_num in (select order_num from OrderItems where prod_id='BR01')) #where 查询 select cust_email from  OrderI...