PHP อยากทราบวิธีคำนวณผลรวมทั้งหมด ในกรณีที่ดึงค่าออกมาจาก database

<table class="table table-bordered">
  <tr class="success">

    
    <td width="9%"> <div align="left"><B>รหัสวัสดุ</B></div></td>
   <td width="30%"> <div align="left"><B>ชื่อวัสดุ</B></div></td>
   <td> <div align="center"><B>จำนวน</B></div></td>
   
    <td> <div align="center"><B>ราคาล่าสุด</B></div></td>
    <td> <div align="center"><B>total</B></div></td>
    <td> <div align="center"><B>หน่วย</B></div></td>
   <!-- <td> <div align="center"><B>ราคา/หน่วย</B></div></td>
    <td> <div align="center"><B>หน่วย</B></div></td>
    <td width="12%"> <div align="center"><B>ประเภทกลุ่มย่อย </B></div></td>
     <td> <div align="center"><B>ประเภทวัสดุ</B></div></td>-->
    
    
   
  </tr>
    
  <?
$sql1="SELECT * FROM tb_approxmately t1 
LEFT JOIN tb_user t2 on t2.user_id=t1.user_id 
LEFT JOIN tb_item_all t3 on t1.item_id=t3.item_id
LEFT JOIN tb_unit t4 on t3.unit_id=t4.unit_id
INNER JOIN  (SELECT  a.* 
             FROM tb_price_tiem_all a
						INNER JOIN (
									SELECT  item_id, MAX(create_date) create_date
									FROM    tb_price_tiem_all
									GROUP BY item_id
									) b ON a.item_id = b.item_id AND a.create_date = b.create_date
            )as p ON t3.item_id = p.item_id 
WHERE t1.listno = '$listno' AND t1.ISdelete ='0' 
ORDER BY t3.item_id ASC  ";
#echo"$sql1";
$res1=mysql_query($sql1);
$i=1;
while($arr1=mysql_fetch_array($res1)){
	$item = $arr1["number_adjust"];
	$price=$arr1["price_item"];
	$total = $item*$price;
	
	?>
    <tr>
    
    <td align="left"><font size="-1" color="#0000FF"><?php echo $arr1["item_code"];?></font></td>
    <td align="left"><font size="-1" color="#0000FF"><?php echo $arr1["item_all_name"];?></font></td>
    <td align="center"><font size="-1" color="#0000FF"><?php echo $arr1["number_adjust"];?> <?php echo $arr1["unit_name"];?></font></td>
   
    <td align="center"><font size="-1" color="#0000FF"><?php echo $arr1["price_item"];?></font></td>
    <td align="center"><font size="-1" color="#0000FF"><?php echo number_format($total,2,'.',','); ?></font></td>
     <td align="center"><font size="-1" color="#0000FF">บาท</font></td>
   
     
    
    
    
	
  </tr>
 
   <? 
 
   }
   


		}
  ?>
<tr class="danger">

    
   
   <td colspan="4"> <div align="right"><B><h4>รวม</h4></B></div></td>
   
    
    <td> <div align="center"><B><h4>......ยังคำนวณไม่ได้.......</h4></B></div></td>
    <td> <div align="center"><B><h4>บาท</h4></B></div></td>

    
   
  </tr>

</table>