The outer query selects students.
Inside the query:
EXISTS checks whether there is at least one course from department number 5.
The inner EXISTS checks whether the same student has enrolled in that course.
So the query means:
Find students who have enrolled in at least one course offered by department number 5.
It does not check all courses. For all courses, double NOT EXISTS would be required.
Online Test Series, Information About Examination,
Syllabus, Notification
and More.
Online Test Series, Information About Examination,
Syllabus, Notification
and More.