Wrong timestamp conversion in mysql database

Question

I'm trying to group timestamps into slots of 15 Minutes. I'm using the following sql statement to retrieve time data from my mysql database.

select
  floor(unix_timestamp(timestamp)/(15*60)) as "Time"
from Table;

That results in a table looking like this:

Time
1846513
1846515
...

The resulting timestamps are converted in grafana where I want to display certain panels.

When applying the time conversion option (transform > Convert field type > Field Time as Time) the timestamps are converted to a different timestamp than they're supposed to. The result looks like this:

Time
1970-01-01 01:30:46.513
1970-01-01 01:30:46.515
...

When only retrieving the timestamps (They come pre converted to datetime) using the following command

select
  timestamp as "Time"
from Table;

I get a result that looks like this:

Time
2022-08-30 16:16:07
...

How can I get the right time conversion?

Any help is appreciated. :)

Answer 1

Don't forget to multiply back the 15*60 after you divide and use FLOOR().

15 * 60 * floor(unix_timestamp(timestamp)/(15*60))