mySQL - winning streak - mysql

Question

Hi I am trying to figure out a way of finding the largest winning streak for each member in my table. When the table was built, this was never in the plans to happen so is why Im seeking help on how I can achieve this.
My structure is as follows:
id player_id opponant_id won loss timestamp
If it is a persons game, the player id is their id. If they are being challenged by someone, their id is the opponant id and the won loss (1 or 0) is in relation to the player_id.
I want to find the greatest winning streak for each user.
Anyone have any ideas on how to do this with the current table structure.
regards
EDIT
here is some test data, where id 3 is the player in question:
id player_id won loss timestamp
1 6 0 1 2012-03-14 13:31:00
13 3 0 1 2012-03-15 13:10:40
17 3 0 1 2012-03-15 13:29:56
19 4 0 1 2012-03-15 13:37:36
51 3 1 0 2012-03-16 13:20:05
53 6 0 1 2012-03-16 13:32:38
81 3 0 1 2012-03-21 13:14:49
89 4 1 0 2012-03-21 14:01:28
91 5 0 1 2012-03-22 13:14:20

Answer 1

Give this a try. Edited to take into account loss rows
SELECT
d.player_id,
MAX(d.winStreak) AS maxWinStreak
FROM (
SELECT
#cUser := 0,
#winStreak := 0
) v, (
SELECT
player_id,
won,
timestamp,
#winStreak := IF(won=1,IF(#cUser=player_id,#winStreak+1,1),0) AS winStreak,
#cUser := player_id
FROM (
(
-- Get results where player == player_id
SELECT
player_id,
won,
timestamp
FROM matchTable
) UNION (
-- Get results where player == opponent_id (loss=1 is good)
SELECT
opponent_id,
loss,
timestamp
FROM matchtable
)
) m
ORDER BY
player_id ASC,
timestamp ASC
) d
GROUP BY d.player_id
This works by selecting all win/loses and counting the win streak as it goes through. The subquery is then grouped by player_id and the max winStreak as calculated as it looped through is output per-player.
It seemed to work nicely against my test dataset anyway :)
To do this more efficiently I would restructure, i.e.
matches (
matchID,
winningPlayerID,
timeStamp
)
players (
playerID
-- player name etc
)
matchesHasPlayers (
matchID,
playerID
)
Which would lead to an inner query of
SELECT
matches.matchID,
matchesHasPlayers.playerID,
IF(matches.winningPlayerID=matchesHasPlayers.playerID,1,0) AS won
matches.timestamp
FROM matches
INNER JOIN matchesHasPlayers
ORDER BY matches.timestamp
resulting in
SELECT
d.player_id,
MAX(d.winStreak) AS maxWinStreak
FROM (
SELECT
#cUser := 0,
#winStreak := 0
) v, (
SELECT
matchesHasPlayers.playerID,
matches.timestamp,
#winStreak := IF(matches.winningPlayerID=matchesHasPlayers.playerID,IF(#cUser=matchesHasPlayers.playerID,#winStreak+1,1),0) AS winStreak,
#cUser := matchesHasPlayers.playerID
FROM matches
INNER JOIN matchesHasPlayers
ORDER BY
matchesHasPlayers.playerID ASC,
matches.timestamp ASC
) d
GROUP BY d.player_id

Answer 2

SELECT * FROM
(
SELECT player_id, won, loss, timestamp
FROM games
WHERE player_id = 123
UNION
SELECT opponant_id as player_id, loss as won, won as loss, timestamp
FROM games
WHERE opponant_id = 123
)
ORDER BY timestamp
That will give you all the results for one player ordered by timestamp. Then you would need to loop those results and count winning records or else concatenate them all into a string and then use string functions to find your highest 11111 set in that string. That code will vary depending on the language you want to use, but logically those are the two choices.