Re: Returning 0 rows from a PL/PGSQL

On Sun, 20 Feb 2005, Vitaly Belman wrote:

> I have the following plpgsql function:
>
> CREATE OR REPLACE FUNCTION public."temp"(int4)
> RETURNS public.books AS
> $BODY$DECLARE
> old_book books%rowtype;
> BEGIN
> select * into old_book from books
> where book_id = var_book_id;
>
> IF FOUND = false THEN
> return null;
> ELSE
> return old_book;
> END IF;
> END;$BODY$
> LANGUAGE 'plpgsql' VOLATILE;
>
> If the function finds a book with the given ID, it returns its row, if
> it doesn't, it should return no rows at all (naturally it is
> simplified version of what I need). In practice, however, it returns
> either a regular row, or a regular row with all fields set to NULL.

I think you'd need to make the function a set returning one in order to
potentially return no rows (which I think would involve making it returns
setof public.books, doing a return next old_book when found=true and
nothing in the false case and putting a return at the end).