如何按另一个分组的总和分组？

Question

I am trying to do a Group By the sum of another Group By .

What is the correct way to do this in LINQ ?

The below query does not work but it is intended to demonstrate the logic I am tyring to achieve.

from so in TblServiceOrders
join sologs in TblSOLogs on so.SONumber equals sologs.SONumber

where so.DateClosed >= new DateTime(2014,01,17) 
where so.DateClosed <= new DateTime(2014,01,17)
where sologs.ElapsedHours != 0 || sologs.ElapsedMinutes != 0

group new {sologs.ElapsedHours, sologs.ElapsedMinutes} by sologs.SONumber into g
group new {g.Sum (x => x.ElapsedHours), g.Sum (x => x.ElapsedMinutes)} by "Totals" into t

select new {
AverageHours = t.Average (x => x.ElapsedHours)
AverageMins = t.Average (x => x.ElapsedMinutes)
}

Answer 1

I've got the query working below. Now the next mystery is why I can't use it to populate a DataGridView in VS. :-(

Working Query:

from so in TblServiceOrders
join sologs in TblSOLogs on so.SONumber equals sologs.SONumber

where so.DateClosed >= new DateTime(2014,01,17) 
where so.DateClosed <= new DateTime(2014,01,17)
where sologs.ElapsedHours != 0 || sologs.ElapsedMinutes != 0

group new {sologs.ElapsedHours, sologs.ElapsedMinutes} by sologs.SONumber into g
group new {hours = g.Sum (x => x.ElapsedHours), mins = g.Sum (x => x.ElapsedMinutes)} by "Totals" into t

select new {
Average = t.Average (x => (x.hours * 60) + x.mins),
Count = t.Count ()
}

Note the:

hours = g.Sum (x => x.ElapsedHours), mins = g.Sum (x => x.ElapsedMinutes)