Ovo je primer kako ovo moze da se resi u Postgresql bazi
Kreiranje tabele za testiranje:
create table aaa as
select generate_series(1,30);
Brisanje nekih podataka:
delete from aaa where generate_series in (2,5,8);
Upit koji nalazi rupe u sekvenci:
select t1.generate_series , t2.generate_series
from aaa t1 right outer join (select * from generate_series (1,30)) t2
on t1.generate_series=t2.generate_series;
Opis funkcije generate_series:
http://www.postgresql.org/docs/9.2/static/functions-srf.html