Verificando Roles e Grants de um usuário

Select Usuario,Permissao from( Select x.Grantee As Usuario ,y.Granted_Role As Permissao From Dba_Role_Privs X join Role_Role_Privs y on y.Role = x.Granted_Role   union all   Select x.Grantee As Usuario ,y.PRIVILEGE As Permissao From Dba_Role_Privs X join Role_sys_Privs y on y.Role = x.Granted_Role   ) where usuario = upper(&usuario) order by usuario desc