title: Zend Db query to select all IDs
body: <p>How would I write an Zend DB query to select all from the column ID?</p>
  
  <p>So far I have tried: </p>
  
  <pre><code>public function getLatestUserID()
      {
          $ids = $this-&gt;select()
               -&gt;where('id = ?');
          return $ids;
      }
  </code></pre>
  
  <p>But to no avail.</p>