sequence in select

["SunWuKung" <Balazs.Klein@xxxxxxxxxxx>]

Hi,
I put the following into a function. Is this always going to give me a
sequence with an increment of 1 independently from other transactions?
If not what would be the standard way to return a sequence from a
query?

CREATE TEMPORARY SEQUENCE rank_seq;
SELECT nextval('rank_seq') FROM whatever ORDER BY id;
DROP SEQUENCE rank_seq;

thx.
Balázs