Re: Simple question about running a function.

On Fri, Nov 26, 2021 at 9:35 AM SQL Padawan <sql_padawan(at)protonmail(dot)com>
wrote:

> create or replace function test_fn()
> returns VOID as $$
> DECLARE
> BEGIN
> FOR r IN 1..10000 LOOP
>
> SELECT ('a string');
>
> END LOOP;
> END;
> $$ LANGUAGE plpgsql;
>
> Compiles no problems - CREATE FUNCTION is returned as expected.
>

By default there isn't much compiling going on here. The pl/pgsql code is
just a string that gets executed during query execution.

> So, I try:
>
> SELECT test_fn();

> but receive the error:
>
> ERROR: query has no destination for result data
> HINT: If you want to discard the results of a SELECT, use PERFORM instead.
> CONTEXT: PL/pgSQL function test_fn() line 6 at SQL statement
>

It's complaining that "SELECT ('a string')" doesn't have a destination.
The fact that you got it to work when you removed that select and replaced
it with an insert proves that. The CONTEXT line also tells you this in no
uncertain terms.

David J.