Re: Passing a dynamic interval to generate_series()

Igal Sapir <igal(at)lucee(dot)org> writes:
> But this throws an error (SQL Error [42601]: ERROR: syntax error at or near
> "'1 '"):

> SELECT generate_series(
> date_trunc('month', current_date),
> date_trunc('month', current_date + interval '7 month'),
> interval ('1 ' || 'month')::interval
> )

You're overthinking it.

SELECT generate_series(
date_trunc('month', current_date),
date_trunc('month', current_date + interval '7 month'),
('1 ' || 'month')::interval
);
generate_series
------------------------
2024-06-01 00:00:00-04
2024-07-01 00:00:00-04
2024-08-01 00:00:00-04
2024-09-01 00:00:00-04
2024-10-01 00:00:00-04
2024-11-01 00:00:00-04
2024-12-01 00:00:00-05
2025-01-01 00:00:00-05
(8 rows)

It might help to read this:

https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-CONSTANTS-GENERIC

and to experiment with what you get from the constituent elements
of what you tried, rather than trying to guess what they are from
generate_series's behavior. For example,

select (interval '1 ');
interval
----------
00:00:01
(1 row)

select (interval '1 ' || 'month');
?column?
---------------
00:00:01month
(1 row)

regards, tom lane