how to know the character set of an oracle databes

1SELECT * FROM nls_database_parameters WHERE PARAMETER = 'NLS_CHARACTERSET';
2SELECT * FROM v$nls_parameters WHERE PARAMETER = 'NLS_CHARACTERSET';
3-- NLS_CHARACTERSET for VARCHAR2, NLS_NCHAR_CHARACTERSET for NVARCHAR2
4SELECT * FROM database_properties WHERE PROPERTY_NAME
5    IN ('NLS_CHARACTERSET', 'NLS_NCHAR_CHARACTERSET');

1select * from database_properties where PROPERTY_NAME in ('NLS_CHARACTERSET', 'NLS_NCHAR_CHARACTERSET')