PostgreSQL -Loop with query - error

Question

I'm new with PostgreSQL; I used to work with Toad for Oracle. I run the following code and can't make it work.

begin
for prueba in
(select * from a_userid)
loop
update a_userid set user_id2 = nextval('seq_userid') 
where user_id = prueba.user_id;
commit;
end loop;
end;

The error is:

************ Error **********
ERROR: error de sintaxis en o cerca de «for»
SQL state: 42601
Character: 9

With Oracle it used to work that way. I don't know where the problem is. I also tried using:

LANGUAGE 'plpgsql';

at the end... but it didn't change at all.

Answer 1

If I understand correctly what you're trying to achieve you don't need a loop for this. Simple UPDATE will do it

UPDATE a_userid
   SET user_id = nextval('seq_userid');

Here is SQLFiddle demo