Oracle PL/SQL Tutorial/SQL PLUS Session Environment/Timezone

Adjust your session time zone to -08:00

SQL>
SQL>
SQL> create table t(
  2      c1 timestamp with time zone,
  3      c2 timestamp with local time zone
  4  )
  5  /
Table created.
SQL>
SQL> insert into t (c1,c2)values( current_timestamp, current_timestamp );
1 row created.
SQL>
SQL> select * from t;

C1
------------------------------------------------------
C2
------------------------------------------------------
26-OCT-09 10.31.38.026000 AM -06:00
26-OCT-09 10.31.38.026000 AM
1 row selected.
SQL>
SQL> alter session set time_zone = "-08:00";
Session altered.
SQL>
SQL> select * from t;

C1
------------------------------------------------------
C2
------------------------------------------------------
26-OCT-09 10.31.38.026000 AM -06:00
26-OCT-09 08.31.38.026000 AM
1 row selected.
SQL>
SQL> drop table t;
Table dropped.

Alter session to change the time zone

SQL> create table myTable (
  2  starts  timestamp with local time zone );
Table created.
SQL>
SQL> insert into myTable (starts)
  2  values (TIMESTAMP "2001-12-01 15:00:00.000000 EST");
1 row created.
SQL>
SQL> insert into myTable (starts)
  2  values (TIMESTAMP "2001-12-01 17:00:00.000000 PST");
1 row created.
SQL>
SQL> insert into myTable (starts)
  2  values (TIMESTAMP "2001-12-01 20:00:00.000000 GMT");
1 row created.
SQL>
SQL> alter session set time_zone = "-05:00"
  2
SQL> column starts format a30
SQL>
SQL> select starts from myTable;

STARTS
------------------------------
01-DEC-01 01.00.00.000000 PM
01-DEC-01 06.00.00.000000 PM
01-DEC-01 01.00.00.000000 PM
3 rows selected.
SQL> drop table myTable;
Table dropped.
SQL>
SQL>

Determine the database time zone:

SQL> select dbtimezone from dual;

DBTIME
------
+00:00
1 row selected.
SQL>
SQL>
SQL>

Determine your session time zone:

SQL>
SQL> select sessiontimezone from dual;

SESSIONTIMEZONE
------------------------------------------------------
-08:00
1 row selected.
SQL>

If your session time zone is not US/Central Standard Time (-06:00), alter your session to Central Standard time:

SQL>
SQL>
SQL> alter session set time_zone = "-06:00";
Session altered.
SQL>