Rank users in mysql by their total points across multiple rows - mysql

Question

I have very much similar kind of requirement as described in this question.
Rank users in mysql by their points
The only difference is in my data. The above problem has the data where table has only row per student. But in my case there may be a possibility that table contains multiple rows for a single student like this
Student 1 points 80
Student 2 points 77.5
Student 2 points 4.5
Student 3 points 77
Student 4 points 77
So now rank should be calculated based on the SUM of points (total) that user has. So in this case result would be.
Student 2 Rank 1 with 82 points
Student 1 Rank 2 with 80 points
Student 3 Rank 3 with 77 points
Student 4 Rank 3 with 77 points
SQL Fiddle for data
I tried couple of things with the solution of above question but couldn't get the result. Any help would be appreciated.

Answer 1

Using the same query in my previous answer just change the table student for a subquery to combine all records of every student
change [student er] for
(SELECT `id`, SUM(`points`) as `points`
FROM students
GROUP BY `id`) er
SQL DEMO
select er.*,
(#rank := if(#points = points,
#rank,
if(#points := points,
#rank + 1,
#rank + 1
)
)
) as ranking
from (SELECT `id`, SUM(`points`) as `points`
FROM students
GROUP BY `id`) er cross join
(select #rank := 0, #points := -1) params
order by points desc;
OUTPUT
| id | points | ranking |
|----|--------|---------|
| 5 | 91 | 1 |
| 6 | 81 | 2 |
| 1 | 80 | 3 |
| 2 | 78 | 4 |
| 3 | 78 | 4 |
| 4 | 77 | 5 |
| 7 | 66 | 6 |
| 8 | 15 | 7 |

Answer 2

Try this:
select id, points, #row := ifnull(#row, 0) + diff rank
from (select *, ifnull(#prev, 0) != points diff, #prev := points
from (select id, sum(points) points
from students
group by 1
order by 2 desc) x) y
See SQLFiddle

Answer 3

EDITED:
(This should work)
SELECT I.Id, I.Points, Rk.Rank
FROM
(SELECT Id, Points, #Rk := #Rk+1 As Rank
FROM (SELECT id, SUM(points) AS Points
FROM students
GROUP BY id
ORDER BY Points DESC) As T,
(SELECT #Rk := 0) AS Rk) As I
INNER JOIN
(SELECT *
FROM (
SELECT Id, Points, #Rk2 := #Rk2+1 As Rank
FROM (SELECT id, SUM(points) AS Points
FROM students
GROUP BY id
ORDER BY Points DESC) As T1,
(SELECT #Rk2 := 0) AS Rk) AS T2
GROUP BY Points) As Rk
USING(Points)
The output will be:
| Id | Points | Rank |
|----|--------|---------|
| 5 | 91 | 1 |
| 6 | 81 | 2 |
| 1 | 80 | 3 |
| 2 | 78 | 4 |
| 3 | 78 | 4 |
| 4 | 77 | 6 |
| 7 | 66 | 7 |
| 8 | 15 | 8 |
After two Ids in 4th position you'll get the 6th position because 5 Ids are before of the 6th.