Does grade level matter to find which subject is least popular?

https://teamtreehouse.com/library/least-popular-subject-2

WITH CLASS_POPULATION AS (
  SELECT COUNT(STUDENT_ID) AS CLASS_SIZE, CLASS_ID, SUBJECT_ID, 
   SUBJECTS.NAME AS SUBJECTNAME FROM STUDENTS
  JOIN SCHEDULE ON SCHEDULE.STUDENT_ID = STUDENTS.ID
  JOIN CLASSES ON CLASSES.ID = SCHEDULE.CLASS_ID
  JOIN SUBJECTS ON CLASSES.SUBJECT_ID = SUBJECTS.ID
  GROUP BY SUBJECTS.NAME
)

SELECT MIN(CLASS_SIZE), CLASS_POPULATION.SUBJECTNAME FROM CLASS_POPULATION;

I got the same answer as Ben, but had a very different approach. I started by getting all students regardless of grade and then joined out to the classes and subjects tables. Right before the initial query was converted to a CTE, the result set was very different. EX: There were around 512 students taking Math) but the same amount in Puppetry.

This is likely because the Puppetry class isn't restricted to grade level. So the question I have is, does grade level matter for this challenge? Is my code appropriate as-is?

I could see it being important if the report needed to be more granular, but that didn't seem to be what was asked here.

Thanks in advance for the feedback!