Count active users per hour based on two datetime entries

Question

I have a MySQL query question.

In my web app I record the active listeners on my Shoutcast server in a MySQL database table, which includes "created", a datetime field for when they tuned in, and an "updated", a datetime field for the latest time the server polled the Shoutcast server (each minute). Plus, I also retrieve the duration in seconds of there listening session, plus the uid (aka session id) which is unique to each session.

What I would like to do is count the amount of listeners per hour, for example 13:00 = 20 listeners, but I would like to include not only those who are tuned in, so "created" datetime field, but also any listeners who where still listening from the previous hour, so the "update" datetime field.

What query would I need to achieve this. I would only generate 1 days worth of results at a time.

I understand how it would use something similar to "COUNT(id) AS hits" and "GROUP BY", but I'm not sure how to factor in the datetime fields, as the "update" datetime field is constantly updated, as long as the user is still listening. And some users can remain listening for 3 hours+.

Edit

The the main parts of the database schema is: id (int 20), created (datetime), updated (datetime), uid (int 20), duration (int 10).

The desired result would look something similar to:

(Time / hits) 0900 => 10, 1000 => 15, 1100 => 5, 1200 => 8, 1300 => 25

and so on...

This is a query I've used to filter results by country, which uses group by and count():-

SELECT country, COUNT(id) AS hits FROM listeners_log WHERE YEAR(created) = YEAR(NOW()) AND MONTH(created) = MONTH(NOW()) AND duration >= 60

The query also has an added filter on the end, to filter out session that are less than 60 seconds long.

To elaborate a little more, the created field reflects when a user connects/starts a listening session. For example, they tune in at 2016-03-21 15:00:00 that is reflected in the created field. But if they're still listening in 1 hour's time, the update field will read 2016-03-21 16:00:00, but the created field will remain the same.

Update:

I've come up with the following SQL, but this only counts the inital connection, indicated by the created field, and ignores if a use remains connected from one hour to a next.

SELECT HOUR(created), COUNT(id) AS hits FROM listeners_log WHERE DATE(created) = CURDATE() group by HOUR(created)

Answer 1

So you will be only needing to query on 'update' datetime field, because even if a new user comes its entry gets created with 'created' datetime as well as in next update under 'update' datetime, so now your concern will be only to query on 'update' datetime for any particular hour.

SELECT COUNT(id) FROM TABLE_NAME
WHERE update_Field BETWEEN DATE(NOW() - INTERVAL 1 HOUR);

This is a sample query to help you out, I don't have schema now to test it. Modify it in your way and Let me know if it doesn't work.