title: Take each first element of the group by
body: <p>How can I take each first element in the group with EF 5 ?</p>
  <pre><code>      var result = await context.SomeDbSet
            .Where(...)
            .GroupBy(x =&gt; new { x.SomeField, ... })
            .Select(x =&gt; x.First())
            .ToListAsync();
  </code></pre>
  <p>I am getting not supported exception.</p>
  <p>How to correctly rewrite query? Thanks.</p>