Re: Returning 0 rows from a PL/PGSQL

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От Vitaly Belman
Тема Re: Returning 0 rows from a PL/PGSQL
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Msg-id fa96e3c605022013591458c0f9@mail.gmail.com
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Ответ на Re: Returning 0 rows from a PL/PGSQL  (Stephan Szabo <sszabo@megazone.bigpanda.com>)
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Good thinking, it works :)
Thanks.

On Sat, 19 Feb 2005 16:53:52 -0800 (PST), Stephan Szabo
<sszabo@megazone.bigpanda.com> wrote:
> 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).
>
>


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