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

Question

<?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()

Answer 1

num_rows()查询返回的行数.首先执行查询,然后可以检查所获得的行数.

$query 是查询结果对象分配给的变量:

 $query=$this->db->get('av_home');// assign to a variable
 echo $query->num_rows();// then use num rows