总分从高到低排序

Question

I have a table called 'Broadsheet'. This is where all the subject total scores of students in a class are aggregated.

sn	name	math	english	french	total
1	mary	70	65	85	220
2	michael	90	70	95	255
3	sam	80	50	95	225

The total for each subject was gotten with this query

 public function getTotalMarksForStudnets($subject_id,$student_id,$table,$totField){
        $this->db->select($totField);
        $this->db->where('subject_id', $subject_id);  
        $this->db->where('student_id', $student_id); 
        $q = $this->db->get($table);
        if($q->num_rows() > 0){
            return  $q->row()->$totField;
        }else{
            return '0'; 
        }
      }

And displayed with this

<td style="border: 1px solid black; font-size:11px;width:120px;text-align:center;">
            <?php 
              $totalMarks = $this->student_model->getTotalMarksForStudnets($tmrow['subject_id'],$stdName['pstudent_id'],$table,$totField);
             $gtotal =  $gtotal + $totalMarks;
             if($totalMarks!=0){
              $totSubjects =  $totSubjects + 1;
             }
            echo $totalMarks;
            ?></td>

While the overall total was displayed with this

<td style="border: 1px solid black; font-size:11px;width:120px;text-align:center;"><?php echo $gtotal;?></td>

Everything was going fine until I had to sort the table from the highest total score to the lowest. The table should now look like this:

sn	name	math	english	french	total
1	michael	90	70	95	255
2	sam	80	50	95	225
3	mary	70	65	85	220

Here, I get really stuck. How do I go from here?

okay, as suggested by @titi, I did a group_by query and came up with this:

 public function getOverallMarksForStudnets($subject_id,$student_id,$table,$totField){
        $this->db->select_sum($totField);
        $this->db->where('subject_id', $subject_id);  
        $this->db->where('student_id', $student_id); 
        $this->db->group_by('subject_id', $subject_id);  
        $this->db->group_by('student_id', $student_id);
        $this->db->order_by($totField, 'DESC');
        $q = $this->db->get($table);
        if($q->num_rows() > 0){
            return  $q->row()->$totField;
        }else{
            return '0'; 
        }
      }

If this is correct, how do I display it?

After using this query,

 public function getTotalMarksForStudnets($subject_id,$student_id,$table,$totField){
       $this->db->select_sum($totField);
       $this->db->group_by( 'student_id', 'subject_id' );
       $this->db->order_by( $totField , 'DESC');
       $q = $this->db->get($table);
        if($q->num_rows() > 0){
            return  $q->row()->$totField;
        }else{
            return '0'; 
        }
      }

I get this:

sn	name	math	english	french	total
1	mary	255	255	255	255
2	michael	255	255	255	255
3	sam	255	255	255	255

My database schema is like this:

CREATE TABLE `scores_primary` (
  `id` int(20) NOT NULL,
  `student_id` int(11) DEFAULT NULL,
  `class_id` int(5) DEFAULT NULL,
  `section_id` int(5) DEFAULT NULL,
  `subject_id` int(11) DEFAULT NULL,
  `session_id` int(11) DEFAULT NULL,
  `ca1` int(11) DEFAULT NULL,
  `ca2` int(11) DEFAULT NULL,
  `ca3` int(11) DEFAULT NULL,
  `ca4` int(11) DEFAULT NULL,
  `ca5` float(10,1) DEFAULT NULL,
  `ca6` float(10,1) DEFAULT NULL,
  `project` int(11) DEFAULT NULL,
  `affective` int(11) DEFAULT NULL,
  `psychomotor` int(11) DEFAULT NULL,
  `exam` int(11) DEFAULT NULL,
  `tot_score` int(11) DEFAULT NULL,
  `created_at` datetime NOT NULL DEFAULT current_timestamp(),
  `modified_at` datetime NOT NULL DEFAULT current_timestamp()
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

tot_score ($totField) is what is collected in this broadsheet table under the various subjects. $totalmarks is sum total of all tot_score ($totField). This is what I want to use to sort the scores.

Answer 1

You can add an order by statement in your query

$this->db->order_by( $totField, 'DESC');

DESC for descending or ASC for ascending

Edited

What about something like this:

$this->db->select( SUM($totField) );
$this->db->group_by( 'student_id', 'subject_id' );
$this->db->order_by( $totField , 'DESC');
$q = $this->db->get($table);

The result will be an array with total score for each pair of student / subject, and ordered by total score.