alias required by standard or PostgreSQL?

Hi,

If I run the query 

"select * from (select * from table_name)" 

PostgreSQL complains with 

ERROR:  subquery in FROM must have an alias
HINT:  For example, FROM (SELECT ...) [AS] foo.

Is the alias required by the ISO standard or is this a PostgreSQL
requirement?

TIA

-- 
Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
web: www.askesis.nl