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Asked: 2026-05-11T08:39:17+00:00

I have a table of player performance: CREATE TABLE TopTen ( id INT UNSIGNED

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I have a table of player performance:

CREATE TABLE TopTen (   id INT UNSIGNED PRIMARY KEY AUTO_INCREMENT,   home INT UNSIGNED NOT NULL,   `datetime`DATETIME NOT NULL,   player VARCHAR(6) NOT NULL,   resource INT NOT NULL );

What query will return the rows for each distinct home holding its maximum value of datetime? In other words, how can I filter by the maximum datetime (grouped by home) and still include other non-grouped, non-aggregate columns (such as player) in the result?

For this sample data:

INSERT INTO TopTen   (id, home, `datetime`, player, resource) VALUES   (1, 10, '04/03/2009', 'john', 399),   (2, 11, '04/03/2009', 'juliet', 244),   (5, 12, '04/03/2009', 'borat', 555),   (3, 10, '03/03/2009', 'john', 300),   (4, 11, '03/03/2009', 'juliet', 200),   (6, 12, '03/03/2009', 'borat', 500),   (7, 13, '24/12/2008', 'borat', 600),   (8, 13, '01/01/2009', 'borat', 700) ;

the result should be:

id home datetime player resource
1 10 04/03/2009 john 399
2 11 04/03/2009 juliet 244
5 12 04/03/2009 borat 555
8 13 01/01/2009 borat 700

I tried a subquery getting the maximum datetime for each home:

-- 1 ..by the MySQL manual:   SELECT DISTINCT   home,   id,   datetime AS dt,   player,   resource FROM TopTen t1 WHERE `datetime` = (SELECT   MAX(t2.datetime) FROM TopTen t2 GROUP BY home) GROUP BY `datetime` ORDER BY `datetime` DESC

The result-set has 130 rows although database holds 187, indicating the result includes some duplicates of home.

Then I tried joining to a subquery that gets the maximum datetime for each row id:

-- 2 ..join  SELECT   s1.id,   s1.home,   s1.datetime,   s1.player,   s1.resource FROM TopTen s1 JOIN (SELECT   id,   MAX(`datetime`) AS dt FROM TopTen GROUP BY id) AS s2   ON s1.id = s2.id ORDER BY `datetime`

Nope. Gives all the records.

I tried various exotic queries, each with various results, but nothing that got me any closer to solving this problem.

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1 Answer

  1. You are so close! All you need to do is select BOTH the home and its max date time, then join back to the topten table on BOTH fields:

    SELECT tt.* FROM topten tt INNER JOIN     (SELECT home, MAX(datetime) AS MaxDateTime     FROM topten     GROUP BY home) groupedtt  ON tt.home = groupedtt.home  AND tt.datetime = groupedtt.MaxDateTime
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