小编Meg*_*aWm的帖子

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Welcome_model extends CI_Model {

      public function select(){

                  $this->db->get('av_home');
                  echo $this->db->num_rows();

      }
}

上面的代码给出错误,

调用未定义的方法CI_DB_mysql_driver :: num_rows()