get the sum of column using Entity framwork

Question

Hello

i want to implement the following SQL statement using entity framework:

 

select coalesce(SUM(cdin_ActMortgageAmnt),0) from CRM.dbo.CDIndex,CRM.dbo.company  where comp_companyid=cdin_companyid and comp_idcust like '%10319%' and cdin_Deleted is null and cdin_startunstufdate is not null and cdin_Status='InProgress'

i tried to get the sum of cdin_ActMortgageAmnt

 

Company c = db.Companies.Find(750);
      var CGP = (from cd in db.CDIndexes
                 join com in db.Companies on cd.cdin_CompanyId equals com.Comp_CompanyId
                 where
                 com.Comp_IdCust == c.Comp_IdCust &&
                 cd.cdin_Deleted == null &&
                 cd.cdin_startunstufdate == null &&
                 cd.cdin_Status == "InProgress"
                 select new
                 {
                  act=cd.cdin_ActMortgageAmnt

                 }
               );
      var query = CGP.Sum(x => x.act);
      lblSum.Text = query.ToString();

but the query gives me null while tracing?