Multiple group by and Sum LINQ

Question

I have a products sales table that looks like this:

saleDate     prod        qty
10/22/09     soap        10
09/22/09     pills       05
09/25/09     soap            


        

Answer 1

var q = from s in sales
       group s by new {saleDate = s.saleDate.ToString("MM/yy"), s.prod} into g
       select new { g.Key.saleDate, g.Key.prod, qty = g.Sum(s => s.qty) };