var tl = Titles .GroupJoin(Publishers, t => t.Pub_id, p => p.Pub_id, (t, g) => new {temp1 = t, temp2 = g}) .SelectMany(o => o.temp2.DefaultIfEmpty(), (x, p2) => new { title_id = x.temp1.Title_id, title_name = x.temp1.Title, price = x.temp1.Price, pub_name = (p2 != null ? p2.Pub_name : null) }); tl.Dump();