Question

I have a huge list ranked by various values (eg. scores)

So I grab the list ordered by these values:

players = Player.objects.order_by('-score', '-karma')

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I would like to:

• Grab a player and get the neighbouring players

P1 score:123

P2 score:122

YOU! score:110

P3 score:90

P2 score:89

• Grab the position!

You are ranked #1234 for score

You are ranked #9876 for karma

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Help would be very much appreciated. thanks 🙂

Answer 1

To get the ranking of the user:

(SELECT * FROM (
  SELECT
    RANK() OVER (ORDER BY Score desc ,Karma desc) AS ranking,
    Id,
    Username,
    Score, karma
  FROM Players 
) AS players_ranked_by_score
where Id = id_of_user 

Where id_of_user is the parameter containing the id of the current player. To get the neighboring players and the current user:

(SELECT * FROM (
  SELECT
    RANK() OVER (ORDER BY Score desc ,Karma desc) AS ranking,
    Id,
    Username,
    Score, karma
  FROM Players 
) AS all_players_ranked
where ranking >= player_ranking - 2 and ranking <= player_ranking + 2;

Where player_ranking is the ranking obtained from the query above.

Hope it helps!

Update: MySQL does not have a rank() function (MS SQL, Oracle, Postgres have one). I looked around and I got this link explaining how to do ranking in MySQL: http://www.artfulsoftware.com/infotree/queries.php?&bw=1024#460.