WHERE CLAUSE 不过滤结果

Question

我在我的模型中有这个工作功能，我试图根据学生的学科成绩来获得学生在班级中的位置。

这是有效的，但 where 子句不会过滤结果以根据主题对它们进行分类。

模型：

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id) 
    {
        $sql = "SELECT `get_tot_score` FROM `exam_group_exam_results` 
WHERE `exam_group_class_batch_exam_subject_id`= `exam_group_class_batch_exam_subject_id` ORDER BY `get_tot_score` DESC";
        $query = $this->db->query($sql);
        return $query->result();
    }

控制器：

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id)
    {
        $data = $this->examresult_model->GetSubjectPosScores($exam_group_class_batch_exam_subject_id); 
        return $data;
    }

看法：

<?php
$scores2 = $CI->GetSubjectPosScores($exam_group_class_batch_exam_subject_id); //echo $value->pos;
$scores = array_column($scores2, 'get_tot_score');
$pos = array_search($exam_result_value->get_tot_score, $scores);
$number = $pos + 1;
 echo $CI->ordinal($number);?>

这就是我通过这个查询得到的：

student_id | subject_id | get_tot_score | Position
---------------------------------------------------
 11        |   1        |   76          |  3rd
 12        |   1        |   90          |  1st
 28        |   6        |   89          |  2nd
 30        |   6        |   70          |  4th

我想要的是这个：

student_id | subject_id | get_tot_score | Position
---------------------------------------------------
 11        |   1        |   76          |  2nd
 12        |   1        |   90          |  1st
 28        |   6        |   89          |  1st
 30        |   6        |   70          |  2nd

Answer 1

问题出在您的查询中

SELECT `get_tot_score` FROM `exam_group_exam_results` 
WHERE `exam_group_class_batch_exam_subject_id`= `exam_group_class_batch_exam_subject_id` ORDER BY `get_tot_score` DESC

基本上您正在检查exam_group_class_batch_exam_subject_id exam_group_class_batch_exam_subject_id的值

这总是正确的

您必须使用某种语句通过您的值$exam_group_class_batch_exam_subject_id更改它（我不知道您使用的是什么库）

编辑我看一下 codignirer 文档

试试这个

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id) 
    {
        $sql = "SELECT `get_tot_score` FROM `exam_group_exam_results` 
WHERE `exam_group_class_batch_exam_subject_id`= ? ORDER BY `get_tot_score` DESC";
        $query = $this->db->query($sql, [$exam_group_class_batch_exam_subject_id]);
        return $query->result();
    }

Answer 2

您在 where 条件中指定了字符串值，而不是在 getSubjectPosScores 函数中作为参数传递的变量的值

在查询中使用 字符串插值

代替

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id) { $sql = "SELECT FROM ，其中WHERE = exam_group_class_batch_exam_subject_id ORDER BY get_tot_score DESC"; $query = $this->db->query($sql); return $query->result(); } DESC"; $query = $this->db->query($sql); return $query->result(); }

有了这个

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id) { $sql = "SELECT get_tot_score FROM exam_group_exam_results WHERE exam_group_class_batch_exam_subject_id= $exam_group_class_batch_exam_subject_id ORDER BY get_tot_score DESC"; $query = $this->db->query($sql); return $query->result(); }

或者

public function GetSubjectPosScores($exam_group_class_batch_exam_subject_id) { $sql = "SELECT FROM ，其中WHERE = '".$exam_group_class_batch_exam_subject_id."' ORDER BY get_tot_score DESC"; $query = $this->db->query($sql); return $query->result(); } DESC"; $query = $this->db->query($sql); return $query->result(); }