Create a spool file with different day time or random number naming convention

Spool in Data format

col spoolname new_value spoolname
select 'invoice_'||to_char(sysdate, 'yymmdd') spoolname from dual;
spool &spoolname
select sysdate from dual;
spool off


Spool in Datatime format

col spoolname new_value spoolname
select 'invoice_'||to_char(sysdate, 'yymmddhh24miss') spoolname from dual;
spool &spoolname
select sysdate from dual;
spool off


Spool file in random format

col Number_rand new_value Number_rand
select to_char(abs(DBMS_RANDOM.random)) Number_rand from dual;
spool &Number_rand
select sysdate from dual;
spool off