How to use join in EntityQuery,.. using RIA and Entities

Question

Hi i use the following patterh for fetching data using RIA objTestAppContext is an instance of LinqToEntitiesDomainService class

EntityQuery query = from tmpTable in objTestAppContext.GteOrdrs() where tmpTable.orderID == d select tmpTable;

Now scenerio is ,, that I also have a OrderDetail entity in EDMS which is attached to he Order as orderID in OrderDetails which is managed by the association set named as FK_orderdetals_orders.

Please tell how can i use join in the "query"