Autoincremental value

Hi I'm a newbie in postgresql, I came from MSSQL, MySQL and now
I'm testing postgres.
In mysql there is a way to make a second autoincrement field, just:

create table table1
(field1 integer,
field2 integer autoincrement,
primary key (field1,field2))

when insert rows:

insert into table1 (field1) values (1);
insert into table1 (field1) values (1);
insert into table1 (field1) values (2);

and then select * from table1, you get:
field1| field2
------+-------
  1   |  1
  1   |  2
  2   |  1
------+-------

there is a way to do this with postgres???

thnx!!!!

--
Saludos,
 adburne
 mailto:adburne@asocmedrosario.com.ar