I have a schema like eg

I want these SQL queries

1. Find the top 4 instructors whose courses have the maximum enrollment in all of their courses combined.

Output columns: InstructorName, TotalEnrollment

Sort by: TotalEnrollment in descending order

2. List all the courses offered by the departments Comp. Sci. and History. Output should not contain any duplicates.

Output columns: DepartmentName, CourseID

Sort by: CourseID in ascending order.

3. List all the courses that have prerequisites offered by a different department.

Output columns: Course_id, Course_department, Prereq_id, Prereq_department

Sort by: Course_id in ascending order

Classroom(building, room number, capacity) Department(dept name, building, budget) Course(course id, title, dept name, credits) Instructori id, name, dept name, salarv) Sectionlcourse id. sec id. semester, vear, building, room number, time slot id) Teaches(i id, course id, sec id, semester, year) Student