dynamic criteria in complex query?

i have search action:




	public function actionDoSearch()

	{

		$condition = null;

		//if has title

		if($_POST['title'])

			$condition = 'sTitle($_POST[\'title\'])->';

		//if has description

		if($_POST['description'])

			$condition .= 'sDescription($_POST[\'description\'])->';

		//i don't know how to make danamic criteria to findAll

		$items = Products::model()->sTitle($_POST['title'])->sDescription($_POST['description'])->with(array(

			'items'=>array('condition'=>'items.visible=1'),

		))->findAll();	

		$this->renderPartial('_items',array(

			'items'=>$items,

		));

	}



please give me a idea,Thanks!

ps:sorry,post in wrong section.