>>>OK. I have a silverlight 4 app. EF datamodel of my SQL database. Domain DataService making my Entities visible.
>>>
>>>Two entity tables are Projects and Change_Requests. Projects has primary key Project_ID. Change Requests has FK Product_ID. Change Requests have a SubdivisionID (int) field.
>>>Now I'm trying to do the equivalent of a join or subquery to get Projects that have Change_Requests in a specific Change_Request.SubdivisionID.
>>>
>>>I've tried..

>>>EntityQuery<Project> query = (from p in _Context.Projects
>>>                                          from c in _Context.Change_Requests
>>>                                          where p.Project_ID == c.Project_ID && c.Subdivision == SubdivisionID
>>>                                          select p);

>>>I get an error ..
>>

>Cannot implicitly convert type 'System.Collections.Generic.IEnumerable<ChangeManagement.Web.Project>' to 'System.ServiceModel.DomainServices.Client.EntityQuery<ChangeManagement.Web.Project>'

>>>How do I get by this?
>>
>>I was going to suggest that you moved this to the Service side but I see elswhere that you have now done that. Just wanted to point out that since you (presumably) have the association between Project and Change_Requests defined in EF you should be able to simplify to something like this:

public IQueryable<Project> GetProjForSubDiv(int SubDivisionId)
>>        {
>>            return (from c in ObjectContext.Change_Requests where c.SubDivision == SubDivisionId select c.Project);
>>        }

and client side becomes something like:

           EntityQuery<Project> query = _Context.GetProjForSubDivQuery(12345);
>>            _Context.Load<Project>(query).Completed += (loadOp, args) =>
>>                {
>>                    var x = ((LoadOperation)loadOp).Entities;
>>                    //or whatever....
>>                };

>
>That foes look a little simpler. I'm still warming up on Linq obviously.
>
>Thanks!

I guess it's not so much a linq thing as taking advantage of the associations built into EF. Took me a while to realize how useful they can be.
Hope it actually works ,BTW, since I couldn't test.....