php基础练习--分页

php分页：

<?php 

    /**

    * php padding

    */



    header("content-type:text/html;charset=utf-8");

    //数据库连接

    $conn = mysql_connect("localhost", "root", "111") or die("not connnected : ".mysql_error());

    mysql_select_db("test", $conn);

    mysql_query("set names utf8");



    //查询共有多少行数据

    $sql1 = "select count(*) from user";

    $ret1 = mysql_query($sql1);

    $row1 = mysql_fetch_row($ret1);

    $tot = $row1[0]; 



    //每页多少行数据

    $length = 5;      

    //总页数  

    $totpage = ceil($tot / $length);



    //当前页数

    $page = @$_GET['p'] ? $_GET['p'] : 1;

    //limit 下限

    $offset = ($page - 1) * $length;



    echo "<center>";

    echo "<h2>php padding</h2>";

    echo "<table width='700px' border='1px' >";

    echo "<tr>";

    echo "<th>ID</th>";

    echo "<th>USER</th>";

    echo "<th>PASS</th>";

    echo "</tr>";



    //将查询出来的数据用表格显示

    $sql2 = "select * from user order by id limit {$offset}, {$length}";

    $ret2 = mysql_query($sql2);

    while ($row2 = mysql_fetch_assoc($ret2)) {

        echo "<tr>";

        echo "<td>{$row2['id']}</td><td>{$row2['name']}</td><td>{$row2['pass']}</td>";

        echo "</tr>";

    }



    echo "</table>";



    //上一页和下一页

    $prevpage = $page - 1;

    if ($page >= $totpage) {

        $nextpage = $totpage;

    } else {

        $nextpage = $page + 1;

    }



    //跳转

    echo "<h3><a href='index.php?p={$prevpage}'>上一页</a>|<a href='index.php?p={$nextpage}'>下一页</a></h3>";

    echo "</center>";

View Code

核心点：<1>“$sql2 = "select * from user order by id limit {$offset}, {$length}";”，$offset、$length和页数之间的关系。

　　　　<2>上一页和下一页的获得方式，以及临界点。