<?php
include_once('conn.php');

$result = mysql_query("SELECT p_class FROM Product group by p_class limit 40");

 mysql_data_seek($result, 0);

    while ($row=mysql_fetch_row($result))
    {
      for ($i=0; $i<mysql_num_fields($result); $i++ )
      {
?>
<table border="1">
  <tr>
    <td><?php echo "$row[$i]";?></td>
    <td>more</td>
  </tr>
  <tr>
    <td colspan="2">********</td>
  </tr>
</table>    
<table border="1">
  <tr>
<?php
$result2 = mysql_query("SELECT * FROM Product where p_class=$row[$i] limit 0,4");
   while ($row=mysql_fetch_row($result2))
    {    
?>  
    <td>
        <table border="1">
            <tr><td>
                   <img src=<?php echo $row['pic'];?> />//这里报错，说写法不对
            </td></tr>
            <tr><td>
                   <?php echo $row['p_class'];?>//这里报错，说写法不对
            </td></tr>
            <tr><td>
                   <?php echo $row['p_name'];?>//这里报错，说写法不对
            </td></tr>
        </table>
          <br />
    </td> 
<?php
    }
?>
  </tr>
</table>
<?php
      } 
    }   
mysql_free_result($result);
mysql_free_result($result2);
mysql_close($conn);
?>