sqlplus   /   as sysdba

show user  查看当前是谁登陆

[oracle@node1 ~]$ sqlplus  /  as sysdbaSQL*Plus: Release 11.2.0.1.0 Production on Mon Jun 5 10:35:05 2017Copyright (c) 1982, 2009, Oracle.  All rights reserved.Connected to:Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit ProductionWith the Partitioning, OLAP, Data Mining and Real Application Testing optionsSQL> show userUSER is "SYS"SQL>

sys 在oracle中最高权限

解锁scott

alter user scott identified by  tiger account unlock;

scott 用户下有几张表

select * from tab；

连接符的用法：用查询生成批量操作的命令

select 'drop table '||tname||';' from tab;

SQL> select 'drop table '||tname||';' from tab;'DROPTABLE'||TNAME||';'------------------------------------------drop table BONUS;drop table DEPT;drop table EMP;drop table SALGRADE;SQL> select * from tab;TNAME                   TABTYPE    CLUSTERID------------------------------ ------- ----------BONUS                   TABLEDEPT                   TABLEEMP                   TABLESALGRADE               TABLESQL>