insert into...

Hi,

i would like to understand why the following INSERT INTO statement works :

INSERT INTO mytable
   SELECT nextval('my_sequence'),
   'myname',
   'myfirstname'
;

whereas usually we should do :

INSERT INTO mytable
VALUES
(
   SELECT nextval('my_sequence'),
   'myname',
   'myfirstname'
);


thanks a lot,

--
Alain
------------------------------------
Windows XP SP2
PostgreSQL 8.2.4 / MS SQL server 2005
Apache 2.2.4
PHP 5.2.4
C# 2005-2008