PHP分页原理

<?php
 $conn=@mysql_connect(“localhost”,”root”,”123456″) or die(“数据库连接失败”);
 $select_db=@mysql_select_db(“test”) or die(“数据库不存在或者不可用”);         //*************连接数据库
 @mysql_query(“set names ‘gb2312′”);        //**************设置字符集
 $sql=mysql_query(“select * from `admin`”) or die(“SQL语句执行失败”);
 //************************分页开始
 $pagesize=5;                            //*******每页显示记录数
 $total=mysql_num_rows($sql);   //*******总记录数
 $totalpage=ceil($total/$pagesize);  //*******总页数
 if(isset($_GET[‘page’]))    //*******设置页码
  {
   $page=$_GET[‘page’];
  }
 else
  {
   $page=1; 
  }     
 
 $start=$pagesize * ($page-1);   //*******每一页显示数据开头始
 $mysql=mysql_query(“select * from admin  order by id desc limit $start ,$pagesize”) or die(“分页查询失败”);
 echo “<table border=1>”;
 echo “<tr>”;
 echo “<td>ID</td>”;
 echo “<td>备注</td>”;
 echo “</tr>”;
 while($row=mysql_fetch_array($mysql))
 {
  $id=$row[0];
  $beizhu=$row[3];
  echo “<tr>”;
  echo “<td>$id</td>”;
  echo “<td>$beizhu</td>”;
  echo “</tr>”; 
 }
 echo “</table>”;     //********显示结果
 echo “每页显示{$pagesize}记录”;echo “共{$totalpage}页<br />”;
 if($page!=1)       //********不是第一页输出上一页
 {
  $pageup=$page-1;
  echo “<a href=’?page=1′>首页</a>”;
 echo “<a href=’?page=$pageup’>上一页</a>”;
 }
 if($page<$totalpage)       //*******不是最后一页输出下一页
 {
  $pagedown=$page+1;
  echo “<a href=’?page=$pagedown’>下一页</a>”; 
  echo “<a href=’?page=$totalpage’>末页</a>”;
 }
 mysql_close();
 ?>

CREATE TABLE `admin` (
   `id` int(4) NOT NULL auto_increment,
   `admin` varchar(10) character set gb2312 collate gb2312_bin NOT NULL,
   `password` varchar(10) character set gb2312 collate gb2312_bin NOT NULL,
   `beizhu` text character set gb2312 collate gb2312_bin,
   `other` varchar(20) character set gb2312 collate gb2312_bin NOT NULL,
   PRIMARY KEY  (`id`)
 );