how to show error if $produk_id and $grup id nothing in db

$grup_id=$this->input->get('grup_id');
        $produk_id=$this->input->get('produk_id');
        $get=$this->db->get_where('sma_product_prices',array('product_id'=>$produk_id,'price_group_id'=>$grup_id));
        if ($get->num_rows() > 0)
        {
            foreach($get->result() as $data){
                if($data->price!==NULL || $data->price!=="")
                    echo $data->price;
                else
                    echo 'Data tidak ada!';
            }
        }
        else
          echo "Error!";
        }