On 9 Sep 2010, at 13:59, Martín Marqués wrote: > I was looking at rows in a table which are not referenced from another > and found some discrepencies. > > These are the queries (with results): > > SELECT * from grupo_concursantes where codigo NOT IN (SELECT grupo > FROM concursantes); > codigo | numero | evento | escuela > --------+--------+--------+--------- > (0 filas) You're possibly getting bitten by the behaviour of NULL in NOT IN lists. This is an often debated feature of the SQL standard. See for example: development=> \pset null '(null)' Null display is "(null)". development=> SELECT 1 NOT IN (1, 2, 3, 4, NULL); ?column? ---------- f (1 row) development=> SELECT 1 NOT IN (2, 3, 4, NULL); ?column? ---------- (null) (1 row) development=> SELECT 1 NOT IN (2, 3, 4); ?column? ---------- t (1 row) development=> SELECT 1 NOT IN (2, 3, 4, NULL, 1); ?column? ---------- f (1 row) Alban Hertroys -- Screwing up is an excellent way to attach something to the ceiling. !DSPAM:737,4c89101f10402127211624! -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
