php+mysql分頁代碼詳解

<?php  
$perpagenum = 10;//定義每頁顯示幾條  
$total = mysql_fetch_array(mysql_query("select count(*) from a"));//查詢數據庫中一共有多少條數據  
$Total = $total[0];                          //  
$Totalpage = ceil($Total/$perpagenum);//上舍，取整  
if(!isset($_GET['page'])||!intval($_GET['page'])||$_GET['page']>$Totalpage)//page可能的四種狀態  
{  
    $page=1;  
}  
else  
{  
    $page=$_GET['page'];//如果不滿足以上四種情況，則page的值爲$_GET['page']  
}  
$startnum     = ($page-1)*$perpagenum;//開始條數  
$sql = "select * from a order by id limit $startnum,$perpagenum";//查詢出所需要的條數  
echo $sql."  
";  
$rs = mysql_query($sql);  
$contents = mysql_fetch_array($rs);  
if($total)如果$total不爲空則執行以下語句  
{  
    do  
    {  
    $id = $contents['id'];  
    $name = $contents['name'];  
    ?>  
    <table border="0" align="center">  
    <tr>  
    <td>id:  
    <?php echo $id;?>  
    </td>  
    </tr>  
    <tr>  
    <td>name:  
    <?php echo $name;?>  
    </td>  
    </tr>  
    </table>  
    <?php  
    }  
while($contents = mysql_fetch_array($rs));//do....while  
$per = $page - 1;//上一頁  
$next = $page + 1;//下一頁  
echo "<center>共有".$Total."條記錄,每頁".$perpagenum."條,共".$Totalpage."頁 ";  
if($page != 1)  
{  
echo "<a href='".$_SERVER['PHP_SELF']."'>首頁</a>";  
echo "<a href='".$_SERVER['PHP_SELF'].'?page='.$per."'> 上一頁</a>";  
}  
if($page != $Totalpage)  
{  
echo "<a href='".$_SERVER['PHP_SELF'].'?page='.$next."'> 下一頁</a>";  
echo "<a href='".$_SERVER['PHP_SELF'].'?page='.$Totalpage."'> 尾頁</a></center>";  
}  
}  
else如果$total爲空則輸出No message  
{  
echo "<center>No message</center>";  
}  
?>