联表查询，看看错误？ [ 新手入门 ]

$criteria=new CDbCriteria();
$criteria->select='news_title,username,pl_id,pl_content,pl_time';
$criteria->join='JOIN pinglun ON news_id =pl_int  JOIN users ON id=pl_person'; 
$criteria->order='pl_id DESC'; 	 
$dataProvider = new CActiveDataProvider('News',array( 'pagination'=>array( 'pageSize'=>8)));
$this->render('index',array(
    'dataProvider'=>$dataProvider,
));