Ranking Based On Aggregate Sum Derived Table Without #variables - mysql

Question

This is been a headache challenge for me in my project, being a php and or say sql novice.
I must first of all indicate that i'm running this code in php with binded params, since I am using pdo.
Now, as the title indicates, how can I rank students in a class, after having calculated their raw scores from Aggregate Sum Derived Table (From Clause), without #variables in sql. Something like, let assume my data pulled from the database is:
studref Name English Maths Gov
Bd1 Ida 66 78 49
Bd2 Iyan 58 80 69
Bd3 Ivan 44 56 80
Bd4 Iven 63 92 68
Bd5 Ike 69 77 59
So using Aggregate Sum in derived table, I then add another column, which is summation of the marks from the various subjects like:
SUM(THE SCORES) AS accum_raw_scores
studref Name English Maths Gov accum_raw_scores
Bd1 Ida 66 78 49 193
Bd2 Iyan 58 80 69 207
Bd3 Ivan 44 56 80 180
Bd4 Iven 63 92 68 223
Bd5 Ike 69 77 59 205
So, what I want to do next is to add another column, which will represent the rank of each student, based on his/her total score from the subjects. Hence, this is where I want the code below to handle that for me:
1+(SELECT COUNT(*)
FROM (SELECT s.studref, SUM(s.subjectscore) AS total_score
FROM studentsreports s
GROUP BY s.studref) AS sub
WHERE sub.total_score > main.accum_raw_scores) AS overall_position,
So that in the end, I will have something like:
studref Name English Maths Gov accum_raw_scores rank
Bd1 Ida 66 78 49 193 4
Bd2 Iyan 58 80 69 207 2
Bd3 Ivan 44 56 80 180 5
Bd4 Iven 63 92 68 223 1
Bd5 Ike 69 77 59 205 3
Unfortunately, I have tried several approaches but to no success. Please help!
Meanwhile, I want to try as much as possible to do without variables.