On 23 April 2016 at 07:08, Manuel Gómez <tar...@gmail.com> wrote: > but its semantics can be rather wonky. Witness: > > postgres=# select 1; > ?column? > ---------- > 1 > (1 row) > > postgres=# select 1 union select 1; > ?column? > ---------- > 1 > (1 row)
Exactly what you would expect. Use UNION ALL to get two rows. > postgres=# select; > -- > (1 row) > > postgres=# select union select; > -- > (2 rows) SELECT with no values is selecting a NULL, and two NULLs do not equate, so you would expect two rows. > postgres=# select 1 intersect select 1; > ?column? > ---------- > 1 > (1 row) > > postgres=# select intersect select; > -- > (2 rows) See above. Geoff -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
