EXTRACT()gets the time zone hour, minute, second, region, and region abbreviation from a TIMESTAMP WITH TIMEZONE returned by TO_TIMESTAMP_TZ() : EXTRACT « Date Timestamp Functions « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. Date Timestamp Functions
3. EXTRACT

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>