Problem with MySQL query for high scores leaderboard - sql

Question

I have a MySQL high scores table for a game that shows the daily high score for each of the past days of the year. Right now I am doing a PHP for-loop and making a separate query for each day, but the table is becoming too large to do that so I would like to condense it into one simple MySQL statement.
Here is my new query right now (date_submitted is a timestamp):
SELECT date(date_submitted) as subDate, name, score FROM highScores WHERE date_submitted > "2009-07-16" GROUP BY subDate ORDER BY subDate DESC, score DESC LIMIT 10;
output:
+------------+------------+--------+
| subDate | name | score |
+------------+------------+--------+
| 2010-07-18 | krissy | 959976 |
| 2010-07-10 | claire | 260261 |
| 2010-07-05 | krissy | 771416 |
| 2010-06-19 | krissy | 698031 |
| 2010-06-18 | otli | 264898 |
| 2010-06-15 | robbie | 82303 |
| 2010-06-01 | dad | 480469 |
| 2010-05-29 | vicente | 124149 |
| 2010-05-27 | dad | 564007 |
| 2010-05-26 | caleb | 502623 |
+------------+------------+--------+
My problem is that when it grouped by subDate, it took the highest score for the earliest timestamp of that day, as you can see in the next query:
SELECT name, score, date_submitted FROM highScores WHERE date(date_submitted)='2010-06-15' GROUP BY name ORDER BY score DESC;
output:
+--------+--------+---------------------+
| name | score | date_submitted |
+--------+--------+---------------------+
| john | 304095 | 2010-06-15 22:58:02 |
| april | 247126 | 2010-06-15 21:25:31 |
| orli | 166021 | 2010-06-15 21:25:31 |
| robbie | 82303 | 2010-06-15 11:38:39 |
+--------+--------+---------------------+
As you can see, poor john should have been the leader for 2010-06-15. Can anyone help? Hopefully it is something real simple I am overlooking. I tried using max(score) before the FROM part in the 1st query and it gave me the correct score but didn't carry over the name.
Thank you for any help.

Answer 1

SELECT userName, userScore, subDate FROM (
SELECT
userName,
userScrore,
DATE(submitDate) as subDate,
#rn := CASE WHEN #subDate = DATE(submitDate)
THEN #rn + 1
ELSE 1
END AS rn,
#subDate := DATE(submitDate)
FROM (SELECT #subDate := NULL) vars, highScores
ORDER BY submitDate, userScore DESC
) deriv
WHERE rn=1;
See also the answer to another 'highest record per something'-question

Answer 2

Add a
ORDER BY userScore DESC
at the end of the second query.