Postgres generate date series with exactly 100 steps

Question

Lets say we have the dates

'2017-01-01'
and
'2017-01-15'

and I would like to get a series of exactly N timestamps in between these dates, in this case 7 dates:

SELECT * FROM 
    generate_series_n(
        '2017-01-01'::timestamp,
        '2017-01-04'::timestamp,
        7
    )

Which I would like to return something like this:

2017-01-01-00:00:00
2017-01-01-12:00:00
2017-01-02-00:00:00
2017-01-02-12:00:00
2017-01-03-00:00:00
2017-01-03-12:00:00
2017-01-04-00:00:00

How can I do this in postgres?

Answer 1

Possibly this can be useful, using the generate series, and doing the math in the select

select '2022-01-01'::date + generate_series *('2022-05-31'::date - '2022-01-01'::date)/15 
FROM generate_series(1, 15)
;

output

  ?column?
------------
 2022-01-11
 2022-01-21
 2022-01-31
 2022-02-10
 2022-02-20
 2022-03-02
 2022-03-12
 2022-03-22
 2022-04-01
 2022-04-11
 2022-04-21
 2022-05-01
 2022-05-11
 2022-05-21
 2022-05-31
(15 rows)