SQL查找表

Question

我的问题是：

select 
    C.GradePoint, D.Domain
from
    (select 
         A.course_code, B.course_title, A.GradePoint
     from
         (select 
              course_code, GradePoint
          from 
              CoursesResult$
          where 
              roll_number = '42472' and GradePoint != 'I' 
              and GradePoint != 'F' and GradePoint != 'D-' 
              and GradePoint != 'D+' and GradePoint != 'D'
              and GradePoint != 'C-' and GradePoint != 'C'
              and GradePoint != 'C+') A  
     join Courses$ B on A.course_code=B.course_code) C 
     join Domains$ D on C.course_title=D.Courses

输出：

GradePoint         Domain
1.    B+        Software Developer
2.    B-        Software Developer
3.    B-        Software Developer
4.    B-        Project Management
5.    B-        Business Intelligence and Analytics
6.    B+        Business Intelligence and Analytics
7.    B+        Business Intelligence and Analytics
8.    B-        Game Development
9.    B             Game Development
10.    B-       Database Administrator
11.    B-       Database Administrator
12.    B        Database Administrator

现在每个年级的编号是

1. B=3
2. B+ =4
3. B- =2

我要计算每个域的分数。

所需产出：

1. 软件开发人员8
2. 商业智能和分析10
3. 数据库管理员7
4. 诸若此类

有人能帮忙吗？

Answer 1

将前两行替换为：

select 
SUM(CASE C.GradePoint WHEN 'B' THEN 3 WHEN 'B+' THEN 4 WHEN 'B-' THEN 2 ELSE 0 END), 
D.Domain

并在查询的末尾添加GROUP BY D.Domain