3. var st_count = db1.station_level_count.OrderByDescending(x => x.dataDate).DefaultIfEmpty(new station_level_count { bbws_count = 0, xbws_count = 0, dbws_count = 0, sjws_count = 0, total_count = 0 }).First();

2. var st_count = db1.station_level_count.OrderByDescending(x => x.dataDate).FirstOrDefault(new station_level_count { bbws_count = 0, xbws_count = 0, dbws_count = 0, sjws_count = 0, total_count = 0 });