Sorry, apologies about not pasting the code!

    <?php
    $inttotalcredits = 0;

    $result = mysql_query("SELECT * FROM site_products JOIN site_trans ON site_products.product_id = site_trans.trans_product");

    while($row = mysql_fetch_array($result) or die(mysql_error())) :
    ?>

    <tr>
       <td><center><?php echo $row['product_id'] ?></center></td>
       <td><center><?php echo $row['product_name'] ?></center></td>
       <td><center><?php echo $row['product_number'] ?></center></td>
       <td><center><?php echo $row['product_description'] ?></center></td>
       <td><center><?php echo $row['trans_inventory'] ?></center></td>
       <?php
    $inttotalcredits += $row['trans_inventory']; ?>
    </tr>

    <?php endwhile ?>
    </table>
    <center><?php echo $inttotalcredits ?></center>
    </p>
   <p><a href="logout.php">Logout</p>