No Row Selected Problem - JOIN and SUBQUERY in SQL-CodePudding

I've been trying to solve the following problem:

Write a query to display list of subject names and minimum mark scored in 'Software Engineering' and 'Computer Programming' . Give an alias name as MIN_MARK for minimum mark column. Sort the result based on subject name in descending order.

And this is the code I've tried to solved the aforementioned problem:

select s.subject_name, min (m.value) as MIN_MARK
from mark m
join subject s on m.subject_id = s.subject_id 
where m.subject_id in (select subject_id from subject
                       where subject_name = 'Software Engineering' 
                       and subject_name='Computer Programming') 
group by s.subject_name;

And I'm getting the output --> No Rows Selected
Could anyone please tell me how to solve this problem.

CodePudding user response：

Could you please tell me what was the issue?

As I mentioned in the comment the problem is the where filter.

where subject_name = 'Software Engineering' 
  and subject_name = 'Computer Programming'

Can the same row be 'Software Engineering' and 'Computer Programming' simultaneously ?

Answer. No

You have to change the where filter from and to or (which ca be written easily as in) .

where subject_name in ('Software Engineering','Computer Programming')

Example