Не используя оконные функции RANK, DENSE_RANK, ROW_NUMBER

Как можно было бы эффективно написать запрос, чтобы получить результаты, аналогичные оконным функциям, представленным ниже?

CREATE TABLE student(course varchar2(10), mark number, name varchar2(10));

INSERT INTO student VALUES
('Maths', 60, 'Thulile'), 

('Maths', 60, 'Pritha'),
('Maths', 70, 'Voitto'),
('Maths', 55, 'Chun'),
('Biology', 60, 'Bilal'),
('Biology', 70, 'Roger');

SELECT
    RANK() OVER (PARTITION BY course ORDER BY mark DESC) AS rank_,
    DENSE_RANK() OVER (PARTITION BY course ORDER BY mark DESC) AS dense_rank_,
    ROW_NUMBER() OVER (PARTITION BY course ORDER BY mark DESC) AS row_number_,
    course, mark, name
FROM student ORDER BY course, mark DESC;

rank_	dense_rank_	row_number_	course	mark	name
1	1	1	Biology	70	Roger
2	2	2	Biology	60	Bilal
1	1	1	Maths	70	Voitto
2	2	2	Maths	60	Thulile
2	2	3	Maths	60	Pritha
4	3	4	Maths	55	Chun

Решение:

with stds as (
   select course, mark, name
     ,(select count(mark) from students t where t.course = e.course and t.mark = e.mark) as sign
     ,(select count(distinct mark) 

       from students t where t.course = e.course and t.mark >= e.mark) as dense_rank_
     ,(select count(1) 

       from students t where t.course = e.course and t.mark||t.name >= e.mark||e.name) as row_number_

   from students e)
select 
          case when sign > 1 then dense_rank_ else row_number_ end as rank_
         ,dense_rank_
         ,row_number_

         ,course, mark, name
from stds
order by course, mark desc, name desc;