ปัญหาการเขียนโค้ดแบ่งหน้า เริ่มการใช้งานโดยการเลือกบทเรียน พอเลือกบทเรียนก็จะมีเนื้อออกมาค่ะ

<?php
<?
include("connect.php");
	if (isset ($_GET['page'] )) {
	$current_page=$_GET['page'];
		}
	else {
	$current_page=1;
	}
$page_size=1;
$start_row=($current_page-1)*$page_size;

$sql="select * from lesson_detail  where lesson_id='$lesson_id'";
$sql .="	LIMIT $start_row, $page_size ; ";
$result = mysql_db_query($dbname, $sql);
echo mysql_error();
$rows=mysql_num_rows($result);

for($i=1;$i<=$rows;$i++)
{ 
$row=mysql_fetch_array($result);
?>
  </div>
<table width="810" height="157" border="2" align="center" bordercolor="#CC33FF">
<tr>
  <td height="30" colspan="2" background="img/img/line/tab_title.gif" bgcolor="#FFCC66">
  <strong>แสดงเนื้อหารายวิชา</strong>  <? echo "$subject_name"; ?>   </td>
</tr>
  <tr>
  <td width="140" height="33" valign="top" background="img/img/line/bggg.jpg" bgcolor="#FFCCFF"><strong>ชื่อเรื่อง : </strong></td>
    <td width="666" valign="top" background="img/img/line/bggg.jpg" bgcolor="#FFCCFF"><?=$row[3] ?></td>
  </tr>
  <tr>
    <td valign="top" background="img/img/line/bggg.jpg" bgcolor="#FFCCFF"><strong>เนื้อหา:</strong></td>
    <td width="666" valign="top" background="img/img/line/bggg.jpg" bgcolor="#FFCCFF"><?=$row[4] ?></td>
  </tr>
  <? } ?>
</table>
<?
$row=mysql_query("SELECT COUNT(*) FROM lesson_detail ; ");
$num_rows=mysql_result($row, 0, 0);
$num_pages=ceil($num_rows/$page_size);

if($current_page!=1){
$prev_page=$current_page - 1;
echo "<a href=\"" . $_SERVER['PHP_SELF']  .  "?";
echo "page=$prev_page\">previous</a>";
}
echo "&nbsp;  Page: $current_page of .$num_pages &nbsp; ";

if($current_page< $num_pages){
$next_page=$current_page+1;
echo "<a href=\"" . $_SERVER['PHP_SELF']  .  "?";
echo "page=$next_page\">next</a>";
}

?>
?>