ASP.net Linq到SQL分组和添加在同一时间？

Question

我的产品

产品表：

ProdID | ProdName 
    1 | shirt 
    2 | pants 

尺寸的表：

SizeID | Size 
    1 | small 
    2 | med 
    3 | large 

订单

OrderID | ProdID | SizeID | Qty 
1  | 1  | 1  | 4 
2  | 1  | 1  | 3 
3  | 1  | 2  | 2 
4  | 2  | 1  | 1 
5  | 2  | 3  | 1 

如何得到这样的结果表：

ProdName | Size | Total qty ordered (group by product and size add all quantities) 
    shirt | small | 7 
    shirt | med  | 2 
    pants | small | 1 
    pants | large | 1 

谢谢

Answer 1

from o in dc.Orders 
group o by new { o.Product.ProdName, o.Size.Size } into g 
select new { g.Key.ProdName, g.Key.Size, Total = g.Sum(or => or.Qty))};