php分页代码实例有注释

    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 "";    echo "php padding";
    echo "";    echo "";    echo "";    echo "";    echo "";    echo "";    //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 "";        echo "";        echo "";    }    echo "ID
USER
PASS






{$row2['id']}
{$row2['name']}
{$row2['pass']}




";
    //上一页和下一页
    $prevpage = $page - 1;
    if ($page >= $totpage) {
        $nextpage = $totpage;
    } else {
        $nextpage = $page + 1;
    }
    //跳转
    echo "
上一页|下一页
";
    echo "
";

分页代码关键点： “$sql2 = "select * from user order by id limit {$offset}, {$length}";”，$offset、$length和页数之间的关系。 上一页和下一页的获得方式，以及临界点。