thinkphp3.2 控制器使用数据库更新问题

控制器代码
<?php
namespace Home\Controller;
use Think\Controller;
use Think\Model;

header("Content-Type:text/html; charset=utf-8");
class IndexController extends Controller {
public function index(){
$db = M('User');
$select = $db->order('id desc')->limit(10)->select();
$this->assign('select',$select);
$this->display();
}
public function update(){
$db = M('User');
$select = $db->where('id='.$_GET['id'])->select();
$this->assign('select',$select);
$this->display(update);
if(isset($_POST['id'])){
$data['user'] = $_POST['user'];
$data['pass'] = md5($_POST['pass']);
$data['address'] = $_POST['address'];
$result=$db->where('id='.$_POST['id'])->save($data);
if($result){
$this->redirect('Index/index','', 2,'数据更新成功');
}
}
}
public function delete(){
$db = M('User');
$result = $db->where('id='.$_GET['id'])->delete();
if($result){
$this->redirect('Index/index','', 2,'数据删除成功');
}
}
}
?>
然后在update页面点击更新后总是出现下面的bug

那里出问题了

$select = $db->where('id='.$_GET['id'])->select(); 的问题 做个 输出一下 看看对不对~