title: Using a Zend_Db_Expr
body: <p>I have the following query:</p>
  
  <pre><code>$select = $this-&gt;getDao()-&gt;select()
                           -&gt;from(
                             array(new Zend_Db_Expr('FROM_UNIXTIME(expiration)'))
                             );
  </code></pre>
  
  <p>The getDao function is a reference to my Data Access object class which looks like this:</p>
  
  <pre><code>class Model_Db_AccountresetDao extends Zend_Db_Table_Abstract
  {
      protected $_name = 'accountreset';
      protected $_primary = 'reset_id';
  }
  </code></pre>
  
  <p>Now i get this following error: </p>
  
  <blockquote>
    <p>"Select query cannot join with another
    table"</p>
  </blockquote>
  
  <p>This while i don't want to do a join. I just want to select that field as a unixTimestamp</p>
  
  <p>How can I solve this problem?</p>
  
  <p>All help is appreciated.</p>
  
  <p>Tnx</p>