CODEWITHSUNDEEP
mysql
user3320142
user3320142

Reputation: 85

MySQL filter for multiple conditions

Assuming i have following table

STUDENTS
--------
StudentID   Course
1           1
1           2
1           3
2           1
2           2
3           1
3           3

Also, I have a certain set of important courses

IMPORTANT COURSE
----------------
Course
1
2
5
8

How can I find out which students take exclusively important courses? (Student 2 in this case)

Upvotes: 0

Views: 57

Answers (1)

juergen d
juergen d

Reputation: 204904

If you group by the student you can count the number of courses that are not in the important courses table. That count should be 0

select studentid
from students s
left join `important courses` c on c.course = s.course
group by studentid
having sum(c.course is null) = 0

Upvotes: 2

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