An AggregatingGroupJoin is a query such as: from c in db.Customers join o in db.Orders on c.CustomerId equals o.Customer.CustomerId into ords join e in db.Employees on c.Address.City equals e.Address.City into emps select new { c.ContactName, ords = ords.Count(), emps = emps.Count() }; where the results of the joins are being fully aggregated and hence do not create any form of hierarchy. This class takes such expressions and turns them into this form: from c in db.Customers select new { c.ContactName, ords = (from o2 in db.Orders where o2.Customer.CustomerId == c.CustomerId select o2).Count(), emps = (from e2 in db.Employees where e2.Address.City == c.Address.City select e2).Count() };

public class AggregatingGroupJoinRewriter

Public Class AggregatingGroupJoinRewriter

public ref class AggregatingGroupJoinRewriter