给定长度的 Postgres generate_series()

Question

We can generate a datetime array with specified bin-width using:

select generate_series( 
  timestamp without time zone '2020-10-01 00:00:00', '2020-10-04 00:00:00', 
  '24 hours') as ts

          ts
1 2020-10-01
2 2020-10-02
3 2020-10-03
4 2020-10-04

Is it possible to generate an array of set length ie a given number of bins/breaks?

I want to provide a date range and number of equal intervals to divide it into.

Answer 1

From the comments:

I want to provide a date range and number of equal intervals to divide it into

You can use generate_series() with integers, and date arithmetics:

with params as (
    select 
        timestamp '2020-10-01' ts_start, 
        timestamp '2020-10-04' ts_end,
        3                      num   
)
select ts_start + (ts_end - ts_start) * i / num as ts
from params
cross join lateral generate_series(0, num) s(i)

This splits the given time range into 3 intervals (resulting in a total of 4 timestamps).

Demo on DB Fiddle :

| ts                  |
| :------------------ |
| 2020-10-01 00:00:00 |
| 2020-10-02 00:00:00 |
| 2020-10-03 00:00:00 |
| 2020-10-04 00:00:00 |