SQL>
SQL> --EXTRACT(): get the time zone hour, minute, second, region, and region abbreviation from a TIMESTAMP WITH TIMEZONE returned by TO_TIMESTAMP_TZ():
SQL>
SQL> SELECT
2 EXTRACT(TIMEZONE_HOUR FROM TO_TIMESTAMP_TZ(
3 '01-JAN-2005 19:15:26 -7:15', 'DD-MON-YYYY HH24:MI:SS TZH:TZM'))
4 AS TZH
5 FROM dual;
TZH
----------
-7
SQL>
SQL>