By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
alter session set nls_territory=RUSSIA
select to_char(sysdate, 'D')
from dual
| TO_CHAR(SYSDATE,'D') |
|---|
| 5 |
alter session set nls_territory=AMERICA
select to_char(sysdate, 'D')
from dual
| TO_CHAR(SYSDATE,'D') |
|---|
| 6 |