Question

I’m trying to do a query that fetches data per hour but instead of the normal group by hour I want to narrow it down and only get the latest hour – meaning the newest data within that hour. With the picture shown below what I wanted to get is the rows with red boxes. If you will notice, first red row is 10:59:51 which means it’s the only row that’s within 10:00:00 and 10:59:59. For the rest of the rows that is on 12:00 and above I wanted to get 12:37:14 because it’s the latest or newest for that hour range.

I have a simple query that groups the data by hour using HOUR() like:

SELECT userid, username, date_created
FROM user_accounts 
WHERE date_created >= '2009-10-27 00:00:00' AND date_created < '2009-10-27 23:59:59'
GROUP BY HOUR(date_created)

The query, however, is just grouping it by hour 10 and 12 which returns id 24 and 25 – but what I needed is id 24 and 28. Any ideas?

Answer 1

Try

SELECT  f.*
FROM    (
        SELECT  MAX(UNIX_TIMESTAMP(date_created)) AS mts
        FROM  user_accounts 
        GROUP BY HOUR(date_created)
        ) s
JOIN    user_accounts  f
ON      UNIX_TIMESTAMP(date_created) = s.mts
WHERE  DATE(date_created) = '2009-10-27'