SELECT tbl_Orders.id, tbl_Orders.FirmaUnvani, tbl_Orders.HizmetTuru, tbl_Orders.SozlesmeNo, tbl_Orders.BelirlenenUcret, Sum(tbl_Bills.FaturaTutar) AS ToplaFaturaTutar, Sum([FaturaTutar]/[tbl_Orders].[BelirlenenUcret]) AS İfade1

FROM tbl_Orders LEFT JOIN tbl_Bills ON tbl_Orders.id = tbl_Bills.Sozlesme_id

GROUP BY tbl_Orders.id, tbl_Orders.FirmaUnvani, tbl_Orders.HizmetTuru, tbl_Orders.SozlesmeNo, tbl_Orders.BelirlenenUcret;