CodeIgniter框架数据库ar类查询分页和总数量的方法

public function pagedata($table_name = '', $where = array(),$like = array(),$page = null,$num = null){          if(empty($table_name)){              return false;          }          /* 获取数量 */          $this->db->select('count(*) AS num');          $this->pagedata_set($table_name,$where,$like);          $query = $this->db->get();          if($query->num_rows() > 0){              $count_result = $query->row_array();              $count = $count_result['num'];          }else{              return null;          }          /* 获取分页数据 */          $this->db->select('*');          $this->pagedata_set($table_name,$where,$like);          if($page != null && $num != null){              $offset = ($page-1)*$num;              $this->db->limit($num,$offset);          }          $query = $this->db->get();                    if($query->num_rows() > 0){              $result = $query->result_array();              $return = array();              $return['count'] = $count;              $return['data'] = $result;              var_dump($return);die();              return $return;          }else{              return null;          }      }      /* 查询条件的集合 */      private  function pagedata_set($table_name,$where,$like){          $this->db->from($table_name);          if(!empty($like)){              $this->db->like($like);          }          if(!empty($where)){              $this->db->where($where);          }          $this->db->where('deleted_at', null);      }