Coalesce in criteria doesnt work




public function defaultScope()

    {

    	$t = $this->getTableAlias(false,false);

    	

        return array(

        	'select' => "{$t}.*,COALESCE(sports_names.name, {$t}.name) as {$t}.name",

	        'join'=>"LEFT JOIN sports_names ON (sports_names.id={$t}.id AND sports_names.lang='".Yii::app()->shortLanguage."')",

        );

    }



in the generated query does not use coalesce. why?