title: Linq to group record by multiple column and select first or default record
body: <p>I am trying to group my table record by multiple column and try to get groups first rows record.Here is the Linq query.</p>
  
  <pre><code>var uploadAddedDate = from up in db.Uploads
                         where up.Url != null
                         orderby up.xxx, up.table1.TeamId
                         group up by new
                         {
                           up.AddedDate,
                           up.xxx,
                           up.table1.TeamId
                          } into upgrp
                          select upgrp;   
  </code></pre>
  
  <p>I want to select each group first rows <code>AddedDate</code> attribute.</p>