Question

I have a table, ‘lasttraces’, with the following fields.

Id, AccountId, Version, DownloadNo, Date 

The data looks like this:

28092|15240000|1.0.7.1782|2009040004731|2009-01-20 13:10:22.000 28094|61615000|1.0.7.1782|2009040007696|2009-01-20 13:11:38.000 28095|95317000|1.0.7.1782|2009040007695|2009-01-20 13:10:18.000 28101|15240000|1.0.7.1782|2009040004740|2009-01-20 14:10:22.000 28103|61615000|1.0.7.1782|2009040007690|2009-01-20 14:11:38.000 28104|95317000|1.0.7.1782|2009040007710|2009-01-20 14:10:18.000 

How can I, in LINQ to SQL, only get the last lasttrace of every AccountId (the one with the highest date)?

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();