>Hi everybody,
>
>I have Invoices table and Transact table that has an invoice_no column (it is currently not marked as FK to invoices, I sent email asking why).
>
>So, as a result the Invoices class doesn't have navigation to transact.
>
>I have the following query:
>
>

>select i.invoice_no, i.descrip1, i.date_time,
>   (select sum(isnull(t.extension,0.00)) from dbo.transact t where t.invoice_no=i.invoice_no) as extension,
>   i.finalized from dbo.invoices i

>
>and this is what I have in C# right now:
>
>

> var invoicesList = _dbSet.Where(x => x.Account == accountName && x.Hidden == false).
>                Select(x => new InvoicesList { InvoiceNo = x.InvoiceNo, Account = x.Account, Hidden = x.Hidden,
>                Descrip = x.Descrip1, Finalized = x.Finalized, Created = x.DateTime});
>
>            if (showFinalized)
>            {
>                invoicesList = invoicesList.Where(x => x.Finalized == true);
>            }

>
>this code is in the Invoices repository class. I'm wondering how can I add the Invoice Balance column into this query.
>
>Once again, right now the transact is not defined as navigation property in the invoices class.
>
>Thanks in advance.

Off the top of my head, if I understood your problem correctly. It would be something like this:

var list = (from  d in _dbSet.Where(x => x.Account == accountName && x.Hidden == false)
               from t in transact .Sum(s=>s.extension).Where(w=>w.extension != null && w.invoiceNo == d.InvoiceNo).
              select(x => new InvoicesList { InvoiceNo = x.InvoiceNo, Account = x.Account, Hidden = x.Hidden, 
                                                          Descrip = x.Descrip1, Finalized = x.Finalized, Created = .DateTime}, InvoiceBalance= t)).ToList();