1. To find the student who has taken the most courses:



SELECT student, COUNT(*) as num_courses
FROM courses
GROUP BY student
ORDER BY num_courses DESC
LIMIT 1;


2. To find the department with the least number of students taking the course "Computer Principles":

SELECT department, COUNT(*) as num_students
FROM students
JOIN departments ON students.student_id = departments.student_id
JOIN courses ON students.student_id = courses.student_id
WHERE courses.name = 'Computer Principles'
GROUP BY department
ORDER BY num_students ASC
LIMIT 1;


3. To find the pass rate for each department (the percentage of courses passed by students in the department):

SELECT department,
SUM(CASE WHEN grades.grade >= 60 THEN 1 ELSE 0 END) / COUNT(*) AS pass_rate
FROM students
JOIN departments ON students.student_id = departments.student_id
JOIN grades ON students.student_id = grades.student_id
GROUP BY department;


FROM ChatGPT