如何在使用 join for MySQL table 时应用 having, group by 子句

Question

我在 MySQL 中有 2 个表 - 问题 Table

QuestionID | QuestionName
-----------|---------------------------------------
1          | How is your faculty communication
-----------|---------------------------------------
2          | How is your study matrial
-----------|---------------------------------------
3          | How your faculty language
-----------|---------------------------------------
4          | Is your faculty cooperative
-----------|---------------------------------------
5          | Is your practical time is enough
-----------|---------------------------------------
6          | Your class starts on time
-----------|---------------------------------------
7          | In practical your doubts are cleared properly
-----------|---------------------------------------
8          | What will you rate for computer
-----------|---------------------------------------
9          | In Theory your questions are replied properly
-----------|---------------------------------------
10         |Your faculty is comes on time
-----------|---------------------------------------

结果Table

RID QID Faculty         Student         Sem Excell  Better  Good Poor
1   1   Ankush          Vishal Deb      III 1       0       0    0
2   2   Ankush          Vishal Deb      III 0       1       0    0
3   3   Ankush          Vishal Deb      III 0       0       1    0
4   4   Ankush          Vishal Deb      III 0       0       0    1
5   5   Ankush          Vishal Deb      III 0       0       1    0
6   6   Ankush          Vishal Deb      III 0       1       0    0
7   7   Ankush          Vishal Deb      III 1       0       0    0
8   8   Ankush          Vishal Deb      III 0       1       0    0
9   9   Ankush          Vishal Deb      III 0       0       1    0
10  10  Ankush          Vishal Deb      III 0       0       0    1
11  1   Mahendra Singh  Mohit Chauhan   III 0       1       0    0
12  2   Mahendra Singh  Mohit Chauhan   III 0       0       1    0
13  3   Mahendra Singh  Mohit Chauhan   III 0       1       0    0
14  4   Mahendra Singh  Mohit Chauhan   III 0       0       0    1
15  5   Mahendra Singh  Mohit Chauhan   III 0       1       0    0
16  6   Mahendra Singh  Mohit Chauhan   III 0       0       1    0
17  7   Mahendra Singh  Mohit Chauhan   III 1       0       0    0
18  8   Mahendra Singh  Mohit Chauhan   III 0       0       0    1
19  9   Mahendra Singh  Mohit Chauhan   III 0       1       0    0
20  10  Mahendra Singh  Mohit Chauhan   III 0       0       0    1

现在我需要显示特定教员在特定学期的记录，但报告应显示该教员在该学期学生中的优秀、较好、良好和差分的总数。

例如，如果第三学期的 5 名学生提交了对 Ankush 的反馈，那么报告应该是这样的——我举了 4 个问题的例子

---------------------------------------------------------------------+
Question                           |Excellent | Better | Good | Poor |
-----------------------------------|----------|--------|------|------|
How is your faculty communication  |    3     |   2    |   0  |  0   |
-----------------------------------|----------|--------|------|------|
How is your study matrial          |    1     |   1    |   3  |  0   |
-----------------------------------|----------|--------|------|------|
How your faculty language          |    0     |   1    |   3  |  1   |
-----------------------------------|----------|--------|------|------|
Is your faculty cooperative        |    1     |   1    |   2  |  1   |
-----------------------------------|----------|--------|------|------|

我试过这个查询，但这不是我需要的

SELECT q.questionname, r.excellent, r.better, r.good, r.poor
FROM question q, result r
WHERE r.facultyid =  'Ankush'
AND r.Semester =  'III'
AND q.questionID = r.questionID

也试过

Select q.questionname, sum(r.excellent),sum(r.better),sum(r.good),sum(r.poor)
from question q,result r 
where r.facultyid='Ankush' and r.Semester='III' and q.questionID=r.questionID;

但是没有成功。请指导我如何获得结果。提前谢谢你。

Answer 1

你的第二个查询非常接近——你刚刚离开了 group by 子句：

Select q.questionname, sum(r.excellent),sum(r.better),sum(r.good),sum(r.poor)
from question q 
    inner join result r on q.questionID=r.questionID
where r.facultyid='Ankush' 
    and r.Semester='III' 
group by q.questionname

另请注意，这使用了明确的 join。一般来说，我建议不要在 from 子句中使用逗号。

如何在使用 join for MySQL table 时应用 having, group by 子句

how to apply having, group by clause while using join for MySQL table

mysql

join

group-by

aggregate-functions

having