Question

I have this SQL script i my app:

select my_seq.nextval from dual connect by level <= 100;

It works great but once I saw (in logs) that it returned no rows at all. Value of sequence is quite far from maximum. I wonder how is it possible at all.

Sequence creation script:

CREATE SEQUENCE my_seq 
MINVALUE 1 MAXVALUE 999999999999999999999999999 
INCREMENT BY 1 START WITH 3602281 
CACHE 2000 NOORDER NOCYCLE;

Answer 1

There is a small possibility that your DUAL table is empty or that you have a local DUAL table? Try:

select 1 from dual;

If no rows then try:

select 1 from sys.dual;