Get the rank of a user in a score table

I have a very simple MySQL table where I save highscores. It looks like that:

Id     Name     Score

So far so good. The question is: How do I get what's a users rank?
For example, I have a users Name or Id and want to get his rank, where all rows are ordinal ordered descending for the Score.

An Example

Id  Name    Score
1   Ida     100
2   Boo     58
3   Lala    88
4   Bash    102
5   Assem   99

In this very case, Assem's rank would be 3, because he got the 3rd highest score.

The query should return one row, which contains (only) the required Rank.

SELECT id, name, score, FIND_IN_SET( score, (
SELECT GROUP_CONCAT( score
ORDER BY score DESC ) 
FROM scores )
) AS rank
FROM scores

gives this list:

id name  score rank
1  Ida   100   2
2  Boo    58   5
3  Lala   88   4
4  Bash  102   1
5  Assem  99   3

Getting a single person score:

SELECT id, name, score, FIND_IN_SET( score, (    
SELECT GROUP_CONCAT( score
ORDER BY score DESC ) 
FROM scores )
) AS rank
FROM scores
WHERE name =  'Assem'

Gives this result:

id name score rank
5 Assem 99 3

You'll have one scan to get the score list, and another scan or seek to do something useful with it. An index on the score column would help performance on large tables.

StackExchange Database Administrators Q#13703, answer score: 44