SQL TEST QUESTIONS:

1) Display all students enrolled in Java course?

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
WHERE c.course_name = 'Java';

output
Arun
Charan

2) Display students whose course is Python?

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
WHERE c.course_name = 'Python';

output
Bala

3) Students whose trainer has more than 5 years experience

SELECT s.student_name
FROM students s
JOIN courses c
ON s.course_id = c.course_id
JOIN trainers t
ON c.trainer_id = t.trainer_id
WHERE t.experience > 5;

Output
Arun
Charan
Divya

4) Display all students, including students not enrolled in any course

SELECT s.student_id, s.student_name, c.course_name
FROM students s
LEFT JOIN courses c
ON s.course_id = c.course_id;

output

student_id	student_name	course_name
1	Arun	Java
2	Bala	Python
3	Charan	Java
4	Divya	Testing
5	Elango	NULL
6	Farah	React

5) Find students who have not enrolled in any course

SELECT student_name
FROM students
WHERE course_id IS NULL;

output
Elango