I have LINQ Script where group by key possibly null. I got the result correctly and now I want to order by first null and then in descending order. because the group by key can be null so I cannot check as .hasValue!

In following approach I am getting null exception as it seems I am not handling null in order correctly?

var v25 = (from transaction in filteredTransactions
       join schedule in schedules on
       new { siteId = transaction.LoginSiteID, startDate = transaction.LoginDateTime.Date, payrollNumber = transaction.PayrollNumber } equals
       new { siteId = schedule.SiteId, startDate = schedule.StartTime.Value.Date, payrollNumber = schedule.PayrollNumber }
          into ezi_s_t
       from scheduleTransactions in ezi_s_t.DefaultIfEmpty()
       group transaction by scheduleTransactions into groupedScheduleTransactions
       select new
       {
           Schedule = groupedScheduleTransactions.Key,
           Transactions = groupedScheduleTransactions.ToList()
       }
     )
     .OrderBy(x=> x.Schedule == null? null : x.Schedule.EziScheduleId)
     .ToList();