C# LINQ Query - Group By

Question

I'm having a hard time understanding how I can form a LINQ query to do the following:

I have a table CallLogs and I want to get back a single result which represents the call that has the longest duration.

The row looks like this:

[ID] [RemoteParty] [Duration]

There can be multiple rows for the same RemoteParty, each which represents a call of a particular duration. I'm wanting to know which RemoteParty has the longest total duration.

Using LINQ, I got this far:

var callStats = (from c in database.CallLogs
                 group c by c.RemoteParty into d
                 select new
                 {
                      RemoteParty = d.Key,
                      TotalDuration = d.Sum(x => x.Duration)
                 });

So now I have a grouped result with the total duration for each RemoteParty but I need the maximum single result.

[DistinctRemoteParty1] [Duration]

[DistinctRemoteParty2] [Duration]

[DistinctRemotePartyN] [Duration]

How can I modify the query to achieve this?

tvanfosson · Accepted Answer · 2009-02-01 13:26:51Z

26

Order the result and return the first one.

var callStats = (from c in database.CallLogs
                 group c by c.RemoteParty into d
                 select new
                 {
                      RemoteParty = d.Key,
                      TotalDuration = d.Sum(x => x.Duration)
                 });

callStats = callStats.OrderByDescending( a => a.TotalDuration )
                     .FirstOrDefault();

edited Feb 1, 2009 at 13:26

answered Jan 31, 2009 at 21:25

tvanfosson

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Comments

flq · Accepted Answer · 2009-01-31 21:50:28Z

4

Have a look at the "Max" extension method from linq

callStats.Max(g=>g.TotalDuration);

answered Jan 31, 2009 at 21:50

flq

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1 Comment

configurator Over a year ago

That would only return the maximum TotalDuration without the RemoteParty part.

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