title: GQL get ID field
body: <p>On google appengine, you can retrieve the hash key value by doing a query like</p>
  
  <pre>
  select __key__ from furniture
  </pre>
  
  <p>But appengine datastore maintains a nicely autoincremented field ID for each kind.</p>
  
  <p>How can I access it from a query? </p>
  
  <pre>
  select ID from furniture
  </pre>
  
  <p>Doesn't work</p>