CSqlDataProvider

public function __construct($sql,$config=array())
{
    $this->sql=$sql;
    foreach($config as $key=>$value)
        $this->$key=$value;
}

protected function calculateTotalItemCount()
{
    return 0;
}

protected function fetchData()
{
    if(!($this->sql instanceof CDbCommand))
    {
        $db=$this->db===null ? Yii::app()->db : $this->db;
        $command=$db->createCommand($this->sql);
    }
    else
        $command=clone $this->sql;

    if(($sort=$this->getSort())!==false)
    {
        $order=$sort->getOrderBy();
        if(!empty($order))
        {
            if(preg_match('/\s+order\s+by\s+[\w\s,\.]+$/i',$command->text))
                $command->text.=', '.$order;
            else
                $command->text.=' ORDER BY '.$order;
        }
    }

    if(($pagination=$this->getPagination())!==false)
    {
        $pagination->setItemCount($this->getTotalItemCount());
        $limit=$pagination->getLimit();
        $offset=$pagination->getOffset();
        $command->text=$command->getConnection()->getCommandBuilder()->applyLimit($command->text,$limit,$offset);
    }

    foreach($this->params as $name=>$value)
        $command->bindValue($name,$value);

    return $command->queryAll();
}

protected function fetchKeys()
{
    $keys=array();
    if($data=$this->getData())
    {
        if(is_object(reset($data)))
            foreach($data as $i=>$item)
                $keys[$i]=$item->{$this->keyField};
        else
            foreach($data as $i=>$item)
                $keys[$i]=$item[$this->keyField];
    }
    return $keys;
}