generate_series is a function to generate a series of values between two points called start and stop. This function has three arguments:
- start is the first value of our series;
- stop is the last possible value of our series;
- step (optional) indicates the interval to generate every value from start to stop. If not indicated, it's equal to one by default.
Examples:
SELECT
*
FROM generate_series(1, 10);
generate_series
-----------------
1
2
3
4
5
6
7
8
9
10
(10 rows)
SELECT
*
FROM generate_series(1, 10, 2);
generate_series
-----------------
1
3
5
7
9
(5 rows)
generate_series is useful also to create a series of dates
SELECT
*
FROM generate_series('2019-1-1'::date, '2019-12-31'::date, '1 Month');
SELECT
*
FROM generate_series('2019-1-1'::date, '2019-12-31'::date, '1 Month');
generate_series
------------------------
2019-01-01 00:00:00-05
2019-02-01 00:00:00-05
2019-03-01 00:00:00-05
2019-04-01 00:00:00-04
2019-05-01 00:00:00-04
2019-06-01 00:00:00-04
2019-07-01 00:00:00-04
2019-08-01 00:00:00-04
2019-09-01 00:00:00-04
2019-10-01 00:00:00-04
2019-11-01 00:00:00-04
2019-12-01 00:00:00-05
(12 rows)
