上次有同学问我，如何查看一个oracle用户具有的权限和角色，我一时没答上来，回头好好研究了一下，记录一下，备查： 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(只能查看登陆用户拥有的角色)所包含的权限sql>select * from role_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 比如我要查看用户 wzsb的拥有的权限：SQL> select * from dba_sys_privs where grantee='WZSB'; GRANTEE                        PRIVILEGE                                ADMIN_OPTION------------------------------ ---------------------------------------- ------------WZSB                           CREATE TRIGGER                           NOWZSB                           UNLIMITED TABLESPACE                     NO比如我要查看用户 wzsb的拥有的角色：SQL> select * from dba_role_privs where grantee='WZSB'; GRANTEE   GRANTED_ROLE   ADMIN_OPTION  DEFAULT_ROLE------------------------------ ------------------------------ ------------ ------------WZSB                           DBA                         NO              YES查看一个用户所有的权限及角色select privilege from dba_sys_privs where grantee='WZSB'unionselect privilege from dba_sys_privs where grantee in (select granted_role from dba_role_privs where grantee='WZSB' );