How does it work internally

I have the following tables: STUDENT (student_id, first_name, last_name, birth_date, year , domain) PROFESSOR (professor_id, first_name, last_name, birth_date, hire_date, title, salary) COURSE (course_id, course_name, professor_id) GRADE (student_id, course_id, grade, date_of_exam) I have to display the students that failed at least at all the courses that student with id = 1 failed. What I tried: SELECT s.student_id, s.first_name, s.last_name, n.grade, n.course_id FROM student s JOIN grade n ON n.student_id = s.student_id WHERE n.grade 1 AND NOT EXISTS ( SELECT 1 FROM GRADE g1 JOIN GRADE g2 ON g1.course_id = g2.course_id WHERE g1.student_id = 1 AND g1.grade 4 );