Group by query in linq

1. orderid customerid
       1          2
       2          3
       3          1

orderid   productname   quantity
   1         A              10
   1        B              15
   1        C              20

Total Quantity per customer:

            total       total     total
             Qty        Qty       Qty
productname   customer1   customer2 customer3  
1               2            3         33
2               3            2         24
3               4           22         34

var query=from p in db.orders
group p.customer by p.orders
into g
select new 
{orders=g.order.tolist()}