PHP에서 이전 페이지와 다음 페이지를 구현하는 방법

<a href="?action=up&id=200">上一篇</a>
<a href="?action=down&id=200">下一篇</a>

$id= $_GET['id'];
//上一篇：
$sql= select * from article where id < &#39;.$id.&#39; order by id desc limit 0,1&#39;;
$rs= mysql_query($sql);
$row= mysql_fetch_array ($rs);
//下一篇：
$sql= select * from article where id < &#39;.$id.&#39; order by id asc limit 0,1&#39;;
$rs= mysql_query($sql);
$row= mysql_fetch_array ($rs);

<?php
 echo GetPreNext(pre,news,$_REQUEST[catid],$_REQUEST[id]);?>
//显示上一篇下一篇
 function GetPreNext($gtype,$table,$catid,$id){
 $preR=mysql_fetch_array(mysql_query("select * from ".$table." where catid=".$catid." and id<$id order by id desc limit 0,1"));//id比传入id小的最近一条
 $nextR=mysql_fetch_array(mysql_query("select * from ".$table." where catid=".$catid." and id>$id order by id asc limit 0,1"));//id比传入id大的最近一条
  $next = (is_array($nextR) ? " where id={$nextR[&#39;id&#39;]} " : &#39; where 1>2 &#39;);
  $pre = (is_array($preR) ? " where id={$preR[&#39;id&#39;]} " : &#39; where 1>2 &#39;);
   $query = "Select * from ".$table." ";
      $nextRow =mysql_query($query.$next);
      $preRow = mysql_query($query.$pre);
      if($PreNext=mysql_fetch_array($preRow))
      {
       echo $PreNext[&#39;pre&#39;] = "上一篇：<a href=&#39;newsshow.php?id=".$preR[&#39;id&#39;]."&&catid=".$catid."&#39;>".$PreNext[&#39;title&#39;]."</a> ";
      }
      else
      {
       echo $PreNext[&#39;pre&#39;] = "上一篇：没有了 ";
      }
      if($PreNext=mysql_fetch_array($nextRow))
      {
       echo $PreNext[&#39;next&#39;] = "下一篇：<a href=&#39;newsshow.php?id=".$nextR[&#39;id&#39;]."&&catid=".$catid."&#39;>".$PreNext[&#39;title&#39;]."</a> ";
      }
      else
      {
        echo $PreNext[&#39;next&#39;] = "下一篇：没有了 ";
      }
}