DataContext.cs

string[] Teletype = new string[] { "00", "01" };
CustomerInfo customInfo = null;

            customInfo = (from p in _context.registry
                          join t in _context.phone on new { key = p.signum } equals new { t.key } into lt
                          join tp in _context.post on new { postnumber = p.postnr, lang = language } equals new { tp.postnumber, tp.lang } into ltp
                          let t = lt.FirstOrDefault()
                          let tp = ltp.FirstOrDefault()
                          where p.signum == signum && t.codetype == "00" && Teletype.Contains(t.teltype)
                          select new CustomerInfo()
                          {
                              FirstName = p.fnamn,
                              LastName = p.lnamn,
                              MainName = p.fnamn,
                              ZipCodeAndName = p.postnr + " " + tp.postlocation,
                              Signum = p.signum,
                              Address = p.adress2 ?? p.adress,
                              Telephone = t.telnr ?? t2.telnr,
                              MainLanguage = p.moderspr,
                              CommunicationLanguage = p.commLang,
                              RegionCode = p.rcode,
                          }).SingleOrDefault();