DBTIMEZONE is one of the vital Date/Time functions of Oracle. It is used to get the database time zone. The result generated is either as a time zone offset or a time zone region name. The DBTIMEZONE function is supported in the various versions of the Oracle/PLSQL, including, Oracle 12c, Oracle 11g, Oracle 10g and Oracle 9i.
Select DBTIMEZONE from dual;
The result depends on the timezone value of the Oracle database.