Mysql – Get the rank of a user in a score table

MySQLrank

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.

Best Answer

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.

Related Solutions

MYSQL score by rank

Using the techniques described here to rank items in MySQL, you can calculate the scores you need using a derived table and some hackery with user variables.

Here's your table with the sample data you provided:

CREATE TABLE blah (
    id INT
  , value INT
);

INSERT blah (id, value)
VALUES 
    (1, 3)
  , (2, 5)
  , (3, 2)
  , (4, 5)
;

And here's the query you need:

-- find the min and max ranks for later use
SELECT
    @min_rank := 1 AS min_rank
  , @max_rank := (SELECT COUNT(DISTINCT value) FROM blah) AS max_rank
;

-- use the calculated min and max ranks to calculate score
SELECT
    id
  , value
  , rank
  , 10.0 * (@max_rank - rank) / (@max_rank - @min_rank) AS score
FROM (
  SELECT
      id
    , value
    , @curr_rank := IF(@prev_rank = value, @curr_rank, @curr_rank + 1) AS rank
    , @prev_rank := value
  FROM blah, (SELECT @curr_rank := 0) r, (SELECT @prev_rank := NULL) p
  ORDER BY value DESC
) ranked_blah;

The output I get for the second query on SQL Fiddle is as follows:

| ID | VALUE | RANK | SCORE |
-----------------------------
|  2 |     5 |    1 |    10 |
|  4 |     5 |    1 |    10 |
|  1 |     3 |    2 |     5 |
|  3 |     2 |    3 |     0 |

Note that this approach will work best if you have an index on value. This will let you find @max_rank quickly using the COUNT technique @ypercube described.

Mysql – score ranking no tie, if tie order by score submit date

Order by Score in descending order, and by SubmitDate in ascending order, then use a variable to give correlative numbers to each row:

mysql> SET @Rank := 0;
Query OK, 0 rows affected (0.00 sec)

mysql> SELECT *, @Rank := @Rank + 1 AS Rank FROM ranking ORDER BY Score DESC, SubmitDate ASC;
+----+-------+-------+---------------------+------+
| Id | Name  | Score | SubmitDate          | Rank |
+----+-------+-------+---------------------+------+
|  4 | Bash  |   102 | 2014-08-04 21:37:17 |    1 |
|  1 | Ida   |   100 | 2014-08-01 21:37:17 |    2 |
|  2 | Boo   |    99 | 2014-08-02 21:37:17 |    3 |
|  3 | Lala  |    99 | 2014-08-03 21:37:17 |    4 |
|  5 | Assem |    99 | 2014-08-05 21:37:17 |    5 |
+----+-------+-------+---------------------+------+
5 rows in set (0.00 sec)

Best Answer

Related Solutions

MYSQL score by rank

Mysql – score ranking no tie, if tie order by score submit date

Related Question