尝试将SYSDBA权限授予SYSTEM，但失败并返回 ORA-65175。

SQL> show user
USER is "SYS"
SQL> grant sysdba to system;
grant sysdba to system
*
ERROR at line 1:
ORA-65175: cannot grant SYSDBA privilege locally in the root

SQL> show con_name

CON_NAME
------------------------------
CDB$ROOT

解决

1.在CDB中授予SYSDBA

在根容器中，在全局范围内将SYSDBA权限授予SYSTEM等普通用户，即CONTAINER=ALL。

SQL> grant sysdba to system container=all;
Grant succeeded.

2.在PDB中授予SYSDBA

SQL> show user
USER is "SYS"
SQL> alter session set container=orclpdb;
Session altered.
SQL> grant sysdba to system;
Grant succeeded.