[bivald]

Samma resultat:

SELECT irc1.date, irc1.id, irc1.users
 FROM irc AS irc1,
    (select DATE_FORMAT(date, '%Y-%m-%d') as datum, MAX(users) AS maxusers
 FROM irc
 GROUP BY datum) AS irc2
 WHERE irc2.datum = date(irc1.date)
    and irc1.users = irc2. maxusers;

Ger:

+---------------------+------+-------+
| date        | id  | users |
+---------------------+------+-------+
| 2007-07-11 00:22:59 | 224 |  403 |
| 2007-07-12 23:55:02 | 794 |  413 |
| 2007-07-13 00:05:02 | 796 |  411 |
| 2007-07-14 00:20:01 | 1087 |  369 |
| 2007-07-16 23:55:01 | 1379 |  431 |
| 2007-07-17 00:05:01 | 1381 |  430 |
| 2007-07-18 00:50:01 | 1678 |  389 |
+---------------------+------+-------+
7 rows in set (0.00 sec)