Time zones

To get time zone of the database:

select DBTIMEZONE from dual;

To get your session time zone:

select SESSIONTIMEZONE from dual;

To change database time zone (instance restart is needed):

alter database set time_zone='Europe/Tallinn'; --or '+02:00'

To change session time zone:

alter session set time_zone='Europe/Tallinn';

To get the list of all time zone names:

select * from v$timezone_names;