Selecting multiple values within a timestamp interval - mysql

Question

I have a (MySQL) table that looks like this:
`radiostation_id` varchar(36) NOT NULL,
`song_id` varchar(36) NOT NULL,
`date` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`length` int(4) NOT NULL
What I want to do is to find every same song_id that has been played within an interval of 15 minutes. It could be that the song was played for example today 15:10 and then again 15:20. So it shouldnt be that i need to set the interval myself, it should check for any interval through the table and list all the songs and timestamps it happened.

Answer 1

It seems to me that you want a song that is played within a certain 15 minutes regardless of the day. There are date and time functions you can use to parse the information you want. For example, you can use TIME() to extract the time portion of your column. For example, you can search for any song played between 12:00 and 12:15 like this:
SELECT DISTINCT id
FROM myTable
WHERE TIME(timeColumn) BETWEEN '12:00:00' AND '12:15:00';
Here is a little SQL Fiddle I used to try it.
EDIT
Based on our discussions in the comments, you can use the following query. It will self join the table on the condition that the song_id matches (so you can compare individual songs), the condition that the time is not exactly the same (so no occurrence is counted twice) and on the condition that the interval in the second table is within +/- 15 minutes of the first like this:
SELECT m.song_id, m.timecolumn
FROM myTable m
JOIN myTable mt
ON m.song_id = mt.song_id
AND m.timeColumn != mt.timeColumn
AND mt.timeColumn BETWEEN DATE_SUB(m.timeColumn, INTERVAL 15 MINUTE) AND DATE_ADD(m.timeColumn, INTERVAL 15 MINUTE);
Here is an updated Fiddle.

Answer 2

It's not entirely clear what you are asking.
If you want to find occurrences of the same song_id, where a second row with the same song_id has a date value within 15 minutes of the first row, one way to get that would be a query like this:
SELECT t.song_id
FROM looks_like_this t
WHERE EXISTS ( SELECT 1
FROM looks_like_this s
WHERE s.song_id = t.song_id
AND s.date >= t.date
AND s.date <= t.date + INTERVAL 15 MINUTE
AND NOT (s.radiostation_id = t.radiostation_id AND s.date = t.date)
If you want to return a unique list of song_id, then add either DISTINCT keyword or a GROUP BY t.song_id clause.
Another way to get the result would be use a JOIN operation:
SELECT t.song_id
FROM looks_like_this t
JOIN looks_like_this s
ON s.song_id = t.song_id
AND s.date >= t.date
AND s.date <= t.date + INTERVAL 15 MINUTE
AND NOT (s.radiostation_id = t.radiostation_id AND s.date = t.date)
GROUP BY t.song_id

Answer 3

The following will show you all the rows where the last played is in the last 15 minutes.
SELECT * FROM myTable
WHERE date>= NOW() - INTERVAL 15 MINUTE
Note that using date in a table column is bad practice as it is a reserved mysql word.

Answer 4

You just need to list out all the songs, when they were played and connect to the same song if it was played again within 15 minutes later.
select pt1.ID, pt1.StartDate, pt2.StartDate StartDate2
from PlayTimes pt1
join PlayTimes pt2
on pt2.ID = pt1.ID
and pt2.StartDate > pt1.StartDate
and pt2.StartDate <= Date_Add( pt1.StartDate, interval 15 minute );
You didn't mention if the radio station played any role. The query above will return a song if it was play again within 15 minutes even on a different station. This makes sense. If you need only those songs played again within 15 minutes on the same station, then add the station id to the join criteria. Would a station ever do that (play the same song twice within 15 minutes)? Or are you checking to make sure a station never does that?