find all exams by student by subjects

students_exams_all_subjects.sql

-- Write your PostgreSQL query statement below
select
    s.student_id,
    s.student_name,
    j.subject_name,
    sum(case when e.subject_name is null then 0 else 1 end) as attended_exams
from
    Students s
Cross join Subjects j
left join Examinations e
on e.student_id = s.student_id and e.subject_name = j.subject_name
group by 1,2,3
order by 1,3