public function returnCompanies() {
$rows=array();
$sql='select cmp_id,cmp_name from companies order by cmp_name ';
$command=Yii::app()->db->createCommand($sql);
$rows=$command->queryAll();;
return $rows;
}
....
$cmps=CHtml::listData(companies::model()->returnCompanies(),'cmp_id','cmp_name') ;