สอบถามเกี่ยวกับ การใช้ pagination ของ ci กับ การ search หน่อยครับ

<?PHP echo form_open('callin/search_sale'); ?>
                <table width="750" border="0" align="center" cellpadding="0" cellspacing="2">
                  <tr>
                    <td width="313" align="right">ค้นหาข้อมูล Sale :</td>
                    <td width="15" align="right">&nbsp;</td>
                    <td width="414">
                      <input name="sale" type="text" />
                      </td>
                  </tr>
                  <tr>
                    <td align="right">&nbsp;</td>
                    <td align="right">&nbsp;</td>
                    <td><input type="submit" name="button" id="button" value="ค้นข้อมูล" /></td>
                  </tr>
                  <tr>
                    <td colspan="3"><hr /></td>
                  </tr>
                </table>
              <?PHP echo form_close(); ?>

public function search_sale(){
	$this->load->library("pagination");
	
	$sale=$this->input->post("sale");
	var_dump($sale);

	if($this->input->post("button")!= null)
		{	
			
			if(empty($sale))
			{
				echo"<script>alert('กรุณากรอกข้อมูล');history.back();</script>"; 
				exit();
			}		
		}
	
	if($sale == ""){
		$sale=$this->uri->segment(4);
	}
	
		$perpage=2;
		$LMT=$this->uri->segment(3)*$perpage;
		$totalrow=ceil($this->erp->count_all('erp_officer')/$perpage);

	    $config["base_url"] = base_url() . "index.php/callin/search_sale";
        $config["per_page"] = 1;
        $config["total_rows"] = $totalrow;
		$config["uri_segment"] = 3;
		


		$sql="SELECT * FROM erp_officer WHERE id LIKE '%".$sale."%' or nickname LIKE '%".$sale."%' or name LIKE '%".$sale."%'";
		$sql.=" limit ".$LMT.",".$perpage."";

		$rs=$this->erp->query($sql);
		$data['rs']= $rs->result_array();


		$this->pagination->initialize($config);
		$this->load->view('callin/add_sale/search_sale',$data);
		  
		
	}