php分页练习

<?php
    require_once('connect.php');
    $sel_query="select * from demotb";
    mysql_query("set names utf8");
    $sel_results=mysql_query($sel_query);
    
    /**
     * 分页信息设置
     * 
     * 1 设置当前页为$apage
     * 2 设置每页显示页数为$pagesize
     * 3 设置总共数量为$totalrows
     * 4 设置最大页数为$maxpage
     */
    
    $page= isset($_GET['page']) ? $_GET['page'] : 1; 
    $pagesize=4;
    $totalrows;
    $totalpage;
    $maxpage;

    $res=mysql_query("select count(*) from demotb");
    $rs=mysql_fetch_array($res);
    $totalrows=$rs[0];
    // echo $totalrows;

    $totalpage=ceil($totalrows/$pagesize);
    // echo $totalpage;
    // 
    if ($page>$totalpage) {
        $page=$totalpage;
    }
    if ($page<1) {
        $page=1;
    }
    $limit=' limit '.($page-1)*$pagesize.','.$pagesize;
    

?>
<table>
    <tr><th>Name:</th><th>Age:</th></tr>
    <?php
        mysql_query('set names utf8');
        $list_query="select * from demotb {$limit}";
        $results=mysql_query($list_query);
        while ($rows=mysql_fetch_assoc($results)) {
            echo '<tr><td>'.$rows['name'].'</td><td>'.$rows['age'].'</td></tr>';
        }
        echo '<tr><td>当前页 :'.$page.'</td><td><a href=list.php?page=1>首页</a></td><td><a href=list.php?page='.($page-1).'>上一页</a></td><td><a href=list.php?page='.($page+1).'>下一页</a></td><td><a href=list.php?page='.($totalpage).'>末页</a></td></tr>';

    ?>
</table>