Question

Lets say I have a table of messages that users have sent, each with a timestamp.

I want to make a query that will tell me (historically) the most number of messages a user ever sent in an hour.

So in other words, in any given 1 hour period, what was the most number of messages sent.

Any ideas?

Answer 1

Assuming timestamp to be a DATETIME – otherwise, use FROM_UNIXTIME to convert to a DATETIME…

For a [rolling] count within the last hour:

  SELECT COUNT(*) AS cnt
    FROM MESSAGES m
   WHERE m.timestamp BETWEEN DATE_SUB(NOW(), INTERVAL 1 HOUR) 
                         AND NOW()
GROUP BY m.user
ORDER BY cnt DESC
   LIMIT 1

If you want a specific hour, specify the hour:

  SELECT COUNT(*) AS cnt
    FROM MESSAGES m
   WHERE m.timestamp BETWEEN '2011-06-06 14:00:00'
                         AND '2011-06-06 15:00:00'
GROUP BY m.user
ORDER BY cnt DESC
   LIMIT 1