title: Find WorkItems that were assigned to X in the last 30 days
body: <p>I'm trying to find all WorkItems that were assigned to a person X in the last 30 days.<br>
  The big problem I have is the "in the last 30 days"-part.</p>
  
  <p>I thought about using the "ever" or "asof" keywords, but couldn't find a good answer yet.. something like <code>WHERE [Assigned To] = 'X' AND (([Assigned To] != 'X') asof '&lt;30daysago&gt;')</code>.<br>
  But this is still not a bulletproof solution.</p>
  
  <p>Any better ideas?</p>
  
  <p>Thanks &amp; kind regards</p>
  
  <p>Simon</p>