oracle常用的一些查询命令

 1.查看所有用户

 select * from dba_users;
 select * from all_users;
 select * from user_users;

 2.查看用户或角色系统权限（直接赋值给用户或角色的系统权限）

 select * from dba_sys_privs;
 select * from user_sys_privs;

 3.查看角色（只能查看登录用户拥有的角色）所包含的权限

 select * fromrole_sys_privs;

 4.查看用户对象权限

 select * from dba_tab_privs;
 select * from all_tab_privs;
 select * from user_tab_privs;

 5.查看所有角色

 select * from dba_roles;

 6.查看用户或角色所拥有的角色；

 select * from dba_role_privs;
 select * from user_role_privs;

 7.查看哪些用户有sysdba 或sysoper系统权限（查询时需要相应权限）

 select * from v$pwfile_users

 比如要查看用户wzsb 的拥有的权限

 select * from dba_sys_privs  where grantee ='wzsb';

 比如要查看用户wzsb拥有的角色

 select * from dba_role_privs where grantee = 'wzsb';

 查看一个用户所拥有的权限及角色

 select privilege from dba_sys_privs where grantee ='wzsb'

 union 

 select privilege from dba_sys_privs where grantee in

 (select granted_role from dba_role_privs where grantee ='wzsb');