How to select only the records with the highest date in LINQ

Question

I have a table, \'lasttraces\', with the following fields.

Id, AccountId, Version, DownloadNo, Date

The data looks like this:

Answer 1

If you just want the last date for each account, you'd use this:

var q = from n in table
        group n by n.AccountId into g
        select new {AccountId = g.Key, Date = g.Max(t=>t.Date)};

If you want the whole record:

var q = from n in table
        group n by n.AccountId into g
        select g.OrderByDescending(t=>t.Date).FirstOrDefault();

Answer 2

If you want the whole record,here is a lambda way:

var q = _context
             .lasttraces
             .GroupBy(s => s.AccountId)
             .Select(s => s.OrderByDescending(x => x.Date).FirstOrDefault());

Answer 3

Go a simple way to do this :-

Created one class to hold following information

• Level (number)
• Url (Url of the site)

Go the list of sites stored on a ArrayList object. And executed following query to sort it in descending order by Level.

var query = from MyClass object in objCollection 
    orderby object.Level descending 
    select object

Once I got the collection sorted in descending order, I wrote following code to get the Object that comes as top row

MyClass topObject = query.FirstRow<MyClass>()

This worked like charm.

Answer 4

It could be something like:

var qry = from t in db.Lasttraces
          group t by t.AccountId into g
          orderby t.Date
          select new { g.AccountId, Date = g.Max(e => e.Date) };

Answer 5

Here is a simple way to do it

var lastPlayerControlCommand = this.ObjectContext.PlayerControlCommands
                                .Where(c => c.PlayerID == player.ID)
                                .OrderByDescending(t=>t.CreationTime)
                                .FirstOrDefault();

Also have a look this great LINQ place - LINQ to SQL Samples