Codeigniter计数行

Question

如何计算数据库中的行？ 我有3张桌子，分别是：

questionnaire
choices
answer_sheet

这是表的结构：

问卷调查

questionnaire_id
type_id_fk
question
answer
pg

选择

choices_id
questionnaire_id_fk
type_id_fk
choices
pg

答题卡

answer_sheet_id
questionnaire_id_fk
choices_id_fk
user_id_fk
status

我的问题是，如何计算unanswered问题和incorrect问题？

这是我的模型：

function countUnanswered($userID, $type) {
        $this->db->select('*');
        $this->db->from('questionnaire q');
        $this->db->join('answer_sheet a', 'q.questionnaire_id=a.questionnaire_id_fk');
        $this->db->where('q.type_id_fk', $type);
        $this->db->where('a.user_id_fk', $userID);
        $query = $this->db->get();
        $rowcount = $query->num_rows();
        return $rowcount;
    }

function countIncorrect($userID, $type) {
        $this->db->select('*');
        $this->db->from('answer_sheet a');
        $this->db->join('questionnaire q', 'q.answer!=a.choices_id_fk', 'LEFT');
        $this->db->where('q.type_id_fk', $type);
        $this->db->where('a.user_id_fk', $userID);
        $query = $this->db->get();
        $rowcount = $query->num_rows();
        return $rowcount;
    }

这是我的看法：

<p><label>Unanswered:</label> <span class="badge"><?php echo $countUnanwered = $this->Mresults->countUnanswered('1'); ?></span></p>
<p><label>Incorrect:</label> <span class="badge"><?php echo $countIncorrect = $this->Mresults->countIncorrect($userID, '1'); ?></span></p>

这是我的控制器

类结果扩展CI_Controller {

   public function view($page = 'results') {
        if (!file_exists(APPPATH . '/views/pages/results/' . $page . '.php')) {
            // Whoops, we don't have a page for that!
            show_404();
        }
        $data['title'] = ucfirst($page) . ' | TOEFL Practice Test'; // Capitalize the first letter
        $data['page'] = $page;
        $this->load->view('template/header', $data);

        if (isset($this->session->userdata['logged_in'])) {
            $data['userID'] = ($this->session->userdata['logged_in']['userID']);
            $data['username'] = ($this->session->userdata['logged_in']['username']);
            $data['email'] = ($this->session->userdata['logged_in']['email']);

            $userID = $this->session->userdata['logged_in']['userID'];

            $this->load->view('pages/results/' . $page, $data);
        } else {
            $this->load->view('pages/user/login_form', $data);
        }

        $this->load->view('template/footer', $data);
    }

}

我在调查表中插入了2个问题，并回答了这2个问题，但在“ 未回答”功能中返回2个问题。 对于错误的函数，它返回3

Answer 1

您尝试使用COUNT函数吗？

例：

 $this->db->select('user_id, COUNT(user_id) as total');
 $this->db->group_by('user_id'); 
 $this->db->order_by('total', 'desc'); 
 $this->db->get('tablename', 10);

你可以在这里看更多

Answer 2

我只是一个人解决问题。

这是我的解决方案：

<?php
   $total = $this->Mresults->totalQuestions('1');
   $answered = $this->Mresults->countAnswered($userID, '1');
   $unAnswered = $total-$answered;
   echo $unAnswered;
?>