Question

嗨，我有一个查询要检索这种格式的学生成绩

Id  subject     class_score total_marks rank    subject_type
1   MATLAB      33.80       73.30       11  Core
1   SCIENCE     39.50       83.00       4   Core
1   ENGLISH     37.60       77.60       8   Elective
1   WQP         43.90       77.40       9   Core
1   BDT         42.00       71.50       12  Elective
1   ART         47.10       84.60       2   Elective
1   COMPUTING   26.00       65.50       13  Elective
2   MATLAB      0.00        0.00        14  Core
2   SCIENCE     38.60       73.60       10  Core
2   ENGLISH     43.80       83.30       3   Elective
2   WQP     45.00       89.00       1   Core
2   BDT     41.00       79.50       6   Elective
2   ART     38.00       78.00       7   Elective
2   COMPUTING   40.80       80.80       5   Elective

我希望通过将所有学生的总成绩（核心科目+该学生选修科目的前三名）相加并计算从头到尾的排名来计算每个学生的总成绩。任何人都可以提供帮助吗？谢谢

我当前的

use  ods_sms;
SELECT  student_id,sum(t.total_marks)score
FROM 
(select 
student_id,total_marks from tab_exam_tracker 
where (subject_type='Core')
 union all select t.student_id,t.total_marks from 
(select student_id,total_marks from tab_exam_tracker 
where subject_type = 'Elective'  order by total_marks desc
limit 3) t
 ) t
GROUP BY student_id

但是得到错误的结果

Answer 1

SELECT 
    t.id,
    SUM(total_marks) AS Core_Marks,
    Elective_Marks
FROM tab_exam_tracker t
INNER JOIN (    
    SELECT id, SUM(total_marks) as Elective_Marks
    FROM  (
        SELECT 
            id, 
            total_marks, 
            IF(@id <> id, @rank:= 1, @rank:= @rank + 1) as rank, 
            @id:= id
        FROM tab_exam_tracker,
        (SELECT @id:= 0 r_id, @rank:= 0 AS r) AS a
        WHERE subject_type = 'Elective'   
        ORDER BY id, total_marks DESC     
    ) as b
    WHERE rank <= 3  
    GROUP BY id
    ) AS e_marks ON t.id = e_marks.id
GROUP BY t.id, Elective_Marks;

找到总分。对于每个学生

1 个答案: