新手简单的PHP分页有关问题，但是不知道为什么不分页

= $page_count) $page = $page_count; 
$select_limit = $page_size; 
$select_from = ($page - 1) * $page_size.','; 
$pre_page = ($page == 1)? 1 : $page - 1; 
$next_page= ($page == $page_count)? $page_count : $page + 1 ; 
$pagenav .= "第 $page/$page_count 页 共 $rows 条记录 "; 
$pagenav .= "首页 "; 
$pagenav .= "前一页 "; 
$pagenav .= "后一页 "; 
$pagenav .= "末页"; 
$pagenav.="　跳到\n"; 
for($i=1;$i<=$page_count;$i++){ 
if($i==$page) $pagenav.="$i\n"; 
else $pagenav.="$i\n"; 
} 
} 

 include("conn.php");

///////////////////////////// 利用pager函数计算出 $select_from 从哪条记录开始检索、$pagenav 输出分页导航 
$rows = mysql_num_rows(mysql_query("select * from manager")); 
echo $rows;
pager($rows,2); 
$sql = "select * from manager limit $select_from $select_limit"; 
echo $sql;
$rst = mysql_query($sql); 

while($row=mysql_fetch_array($rst)){
?>