总结工作中经常用到一些Oracle 11g用户权限管理学习笔记：
1、查看数据库里所有用户各自拥有的角色：
select * from (select distinct connect_by_root grantee username,granted_role
from dba_role_privs
connect by prior granted_role =grantee ) a
where exists (select 1 from dba_users b where b.username=a.username)
order by 1,2
;
2、查看数据库所有用户的系统权限：
select d.username,d.privilege from
(select a.username,b.privilege from
(select distinct connect_by_root grantee username,granted_role
from dba_role_privs
connect by prior granted_role =grantee) a,
(select grantee,privilege from dba_sys_privs) b
where a.granted_role=b.grantee
union
select grantee,privilege from dba_sys_privs) d
where exists((select 1 from dba_users c where d.username=c.username))
order by 1,2;
3、查看数据库所有用户的表权限
select d.username,d.privilege,d.owner,d.table_name from
(select a.username,b.privilege,b.owner,b.table_name from
(select distinct connect_by_root grantee username,granted_role
from dba_role_privs
connect by prior granted_role =grantee) a,
(select grantee,owner,table_name,privilege from dba_tab_privs) b
where a.granted_role=b.grantee
union
select grantee,privilege,owner,table_name from dba_tab_privs) d
where exists((select 1 from dba_users c where d.username=c.username))
order by 1,2;
4、如何查看拥有DBA角色的用户？
常规做法，一般是直接查询DBA_ROLE_PRIVS视图。查询语句如下：
select grantee,granted_role from dba_role_privs where granted_role=’DBA’;
这会漏掉用户，测试如下：
正确的查询应按如下语句查询：
select * from (select distinct connect_by_root grantee username,granted_role
from dba_role_privs
connect by prior granted_role =grantee ) a
where a.granted_role=’DBA’;
5、查看拥有SELECT ANY TABLE权限的用户
对于授予角色的，看看都谁有查询所有表的权限
select distinct rp.grantee from dba_role_privs rp ,dba_sys_privs sp
where rp.granted_role = sp.grantee
and sp.privilege like 'SELECT ANY TABLE%'