How to bin timestamp data into buckets of n minutes in postgres

Question

I have the following query which works, binning timestamped "observations" into buckets whose boundaries are defined by the bins table:

SELECT
  count(id),
  width_bucket(
      time :: TIMESTAMP,
      (SELECT ARRAY(SELECT start_time
                    FROM bins
                    WHERE owner_id = 'some id'
                    ORDER BY start_time ASC) :: TIMESTAMP[])
  ) bucket
FROM observations
WHERE owner_id = 'some id'
GROUP BY bucket
ORDER BY bucket;

I would like to modify this to allow for querying arbitrary n-minute bins starting from a specified timestamp, rather than having to pull from from an actual "bins" table.

That is, given a start time, a "bin width" in minutes, and a number of bins, is there a way I can generate the array of timestamps to pass into the width_bucket function?

Alternatively, is there a different/simpler approach to get the same results?

Answer 1

Use the function generate_series(start, stop, step interval), e.g.

select array(
    select generate_series(
        timestamp '2018-04-15 00:00', 
        '2018-04-15 01:00', 
        '30 minutes'))

                               array                                
---------------------------------------------------------------------
 {"2018-04-15 00:00:00","2018-04-15 00:30:00","2018-04-15 01:00:00"}
(1 row)

Example in Db<>fiddle.