article.php文件代码

// 上一页
    public function lastpages(){
        // $this->dao->where("catid=$data[catid] and id<$id")->order('id desc')->find();
         $id = intval($_GET['id']);
        $sql = "SELECT id,title FROM " . get_table('article')." WHERE id< ".$id." ORDER BY id DESC LIMIT 1";
        $result = $this->query_all($sql);
        if($result){
            return $result;
        }else{
            return $result=false;
        }
    }
    // 下一页
    public function nextpages(){
         $id = intval($_GET['id']);
        $sql = "SELECT id,title FROM " . get_table('article')." WHERE id> ".$id." ORDER BY id ASC LIMIT 1";
        $result = $this->query_all($sql);
        if($result){
            return $result;
        }else{
            return $result=false;
        }
    }

main.php代码

// 上一页
$article_info['last_pagesdb'] = $this->model('article')->lastpages();
//下一页
$article_info['next_pagesdb'] =$this->model('article')->nextpages();

html调用代码

 <p><?php echo $article_info['next_pagesdb']; ?></p>

为什么不能输出上一篇下一篇文章呢？