Question

我有一个场景 - 用户需要完成2组3门课程中的任何一门，然后才能通过。如果他只完成1或2门课程，结果将为0.如果他完成所有课程，则返回结果为1.

必须通过CourseA，CourseB，CourseC才能通过或完成CourseD，CourseE，CourseF传递

Answer 1

如果基表有三列，这将是一个很好的练习题：student_id，course_id和grade（通过/失败），还有另一个课程表，包含course_id和“track”（可能还有其他关于课程的信息））。 “轨道”是指必须通过才能毕业的一组课程;例如，一个“轨道”需要课程A，B，C（假设那些是课程ID），另一个需要D，E，F。

这是一个原型，可能的解决方案。

with
     enrollments ( student_id, course_id, grade ) as (
       select 1001, 'A', 'Pass' from dual union all
       select 1001, 'B', 'Pass' from dual union all
       select 1001, 'D', 'Fail' from dual union all
       select 1001, 'E', 'Pass' from dual union all
       select 1002, 'A', 'Pass' from dual union all
       select 1002, 'C', 'Pass' from dual union all
       select 1002, 'D', 'Pass' from dual union all
       select 1003, 'F', 'Fail' from dual union all
       select 1005, 'A', 'Fail' from dual union all
       select 1005, 'D', 'Pass' from dual union all
       select 1005, 'E', 'Pass' from dual union all
       select 1005, 'F', 'Pass' from dual
     ),
     courses ( course_id, track ) as (
       select 'A', 101 from dual union all
       select 'B', 101 from dual union all
       select 'C', 101 from dual union all
       select 'D', 201 from dual union all
       select 'E', 201 from dual union all
       select 'F', 201 from dual
     )
-- >>  end of test data; the actual solution (SQL query) begins below this line  << --
select   distinct student_id
from     enrollments e join courses c on e.course_id = c.course_id
where    grade = 'Pass'
group by student_id, track
having   count(*) = 3
;

STUDENT_ID
----------
1005

Oracle PLSQL - 如果找到列的组合，如何查询返回结果

1 个答案: