thinkphp 分页出错 $page->render() 出错

1.出错原因可能很简单，就是在查询的时候写的是select，而不是paginate

2.thinkphp多层查询

/**     * 试卷列表     * @param int $page     * @return mixed     */    public function index($name='',$course='', $page=1 ){        $map = [];        if (!empty($name)) {            $map['name'] = ['like', "%{$name}%"];        }        if (!empty($course)) {            $map['course'] = ['like', "%{$course}%"];        }        $paper_list = $this->paper_model->order('id DESC')->paginate( 5, false, ['page' => $page]);        foreach ($paper_list as $item){            $id = $item['id'];            $num = $this->question_model->where("pid=$id")->count();            $item['q_num'] = $num;        }        return $this->fetch('index', ['name'=>$name,'course'=>$course,'paper_list'=>$paper_list]);    }