select c.cust_name, sum(oi.item_price * oi.quantity) as total_price from OrderItems oi inner join Orders o on oi.order_num = o.order_num inner join Customers c on c.cust_id = o.cust_id group by c.cust_name having sum(oi.item_price * oi.quantity) >= 1000 order by total_price;