title: Linq: how to group by, max and orderby
body: <p>i have the following table:</p>
  
  <pre><code>id   serialcode    timestamp
  1       0001       01/02/2015
  2       0001       02/02/2015
  3       0001       03/02/2015
  4       0002       03/02/2015
  </code></pre>
  
  <p>In linq i want get the max id for a single (grouped by) serialcode. After, i want order the results for descending timestamp.</p>
  
  <p>In this example, first, i want extract the following rows:</p>
  
  <pre><code>id   serialcode    timestamp
  3       0001       03/02/2015
  4       0002       03/02/2015
  </code></pre>
  
  <p>Then i'd like to order in descending timestamp.
  How can achieve this in Linq?</p>
  
  <p>Thanks </p>