CI使用原生sql

/**
 * 清除记录
 */
public function clear_apply_row() {
        $trial_id = $this->input->get(‘trial_id‘, ture);
        $phone = $this->get_clear_phone_line();

        $this->load->database();

        $sql = "delete from filorga_trial_apply where apply_telephone=$phone";
        if($trial_id) {
            $sql .=  " and trial_id=$trial_id";
        }
        $res = $this->db->query($sql);
        $num = $this->db->affected_rows();
        echo ‘影响行数:‘ . $num;
        echo "<br />";
        if($res) {
            echo ‘删除申请记录成功‘;
        } else {
            echo ‘删除申请记录失败‘;
        }
    }