title: 'mysql_num_rows(): supplied argument is not a valid argument' when trying to use JDatabase
body: <pre><code>$select = "SELECT * FROM `jos_users`";
  
  $connection-&gt;setQuery($select);
  
  $rows = $connection-&gt;getNumRows();
  </code></pre>
  
  <p>$rows does not work it throws the 'mysql_num_rows(): supplied argument is not a valid' error but...</p>
  
  <pre><code>$result = $connection-&gt;loadObjectList();
  </code></pre>
  
  <p>$result works fine.</p>
  
  <p>Is this a Joomla bug?? Or what am i doing wrong?</p>