Oracle: Time zone related stuff

create table tq84_tz_test (
     ts     timestamp,
     ts_tz  timestamp with time zone
);

alter session set time_zone = 'Europe/Zurich';
insert into tq84_tz_test values (systimestamp, current_timestamp);

alter session set time_zone = 'CST';
insert into tq84_tz_test values (systimestamp, current_timestamp);

select * from tq84_tz_test;

drop table tq84_tz_test;