Just sharing a sample code that could be used for group by and sum operation on EntityCollection.
Suppose below is the output that we want
We can use the below code for that.
// select categoryid, final forecast, final awards from SubCategory Entity
// category id is lookup in SubCategory Entity
EntityCollection result = orgProxy.RetrieveMultiple(new FetchExpression(fetch));
var details = from r in result.Entities.AsEnumerable()
group r by new
{
groupByCategoryID =...
