title: 30 days in Doctrine Symfony
body: <p>i would like add clause where - max 30 days from now.</p>
  
  <p>in database i have timestamp:</p>
  
  <p>2011-08-30 20:29:35</p>
  
  <pre><code>id  | name | date
  1   | aaa  | 2011-08-30 20:29:35
  2   | vvv  | 2011-08-10 20:29:35
  3   | bbb  | 2011-07-10 20:29:35
  4   | fff  | 2011-08-14 20:29:35
  5   | ddd  | 2011-06-10 20:29:35
  
  
  $query = Doctrine_Core::getTable('News')-&gt;createQuery('a');
  $query-&gt;addWhere('date ????????');
  </code></pre>
  
  <p>How can i get all news recent 30 days?</p>