php - Codeigniter : Fatal error: Call to a member function num_rows() on a non-object -

i have problem in link of script codeigniter. have url :-

localhost/index.php/admin/orders/ me order of product, when add character in end of link :

localhost/index.php/admin/orders/ggg user see error message.

fatal error: call member function num_rows() on non-object in  

how can save link, , hidden message.

my controller :-

function orders() {     $data['orders'] = $this->admin_model->getorderlist();     $data['total']  = $this->admin_model->getordercount();     $this->load->view('admin/orders',$data); } 

my model:-

 function getorderlist() {     $page = $this->uri->segment(3);     if($page=='')         $page=1;      $start = ($page-1)*records_per_page;     $end = records_per_page;      $this->db->select("*");     $this->db->limit($end,$start);      $this->db->order_by('order_id','desc');     $result = $this->db->get('wg_orders');     if($result->num_rows()>0)     return $result->result();     else     return 'empty'; } 

you can use count() function well.

in controller

    function orders()     {         $data['orders'] = $this->admin_model->getorderlist();         $data['total']  = $this->admin_model->getordercount();         $this->load->view('admin/orders',$data);     } 

in model

    function getorderlist()     {         $page = $this->uri->segment(3);         if($page=='')             $page=1;          $start = ($page-1)*records_per_page;         $end = records_per_page;          $query = $this->db->query("select * table_name (your_argument) limit $end, $start order order_id desc ");         $result = $query->result_array();         $count = count($result);          if($count>0)         {             return $result;         }         else         {             return 'empty';         }     }