On Thu, Aug 13, 2009 at 12:36 PM, Radoslaw Zielinski<radek@pld-linux.org> wrote:
> Hello,
>
> I have reported this yesterday via WWW as bug 4979, but I can't see it
> in the -bugs archive. Has it been lost or are the bug reports being
> moderated...?
>
> Anyway. Pg 8.4.0 from yum.postgresql.org running on 64bit RHEL 5.3.
>
> radek=# \d kandydaci
> Table "public.kandydaci"
> Column | Type | Modifiers
> -------------------+------------------+-----------
> id_rekordu | bigint | not null
> id_osoby | integer | not null
> id_rodzaju_adresu | smallint |
> score | double precision | not null
> Indexes:
> "kandydaci_pkey" PRIMARY KEY, btree (id_rekordu, id_osoby)
> Check constraints:
> "c_kandydaci_score" CHECK (score >= 0::double precision AND score <= 1::double precision)
> Foreign-key constraints:
> "kandydaci_fk_id_rekordu" FOREIGN KEY (id_rekordu) REFERENCES rekordy(id) ON DELETE CASCADE
>
> radek=# select count(*), sum((r.id is null)::int) as orphans from kandydaci k left join rekordy r on
r.id=k.id_rekordu;
> count | orphans
> -------+---------
> 1472 | 152
> (1 row)
since you do LEFT JOIN, indeed you can get r.id to be null.
--
GJ
