1. 登陆数据库

sqlplus /nologconn heatmeter/heatmeter@orclconn sys/orcl as sysdba

2. 查看数据库名称

select name from v$database;

3. 数据库导入导出

exp water/water@orcl file=c:\water.dmp owner=(water);imp water/water@orcl file=c:\waterexp.dmp full=y;imp water/water@orcl file=c:\waterexp.dmp table=(tabale1) full=y;

4. 删除某个用户的所有表

drop user water cascade;

5. 断开某用户的所有连接

select username,sid,serial# from v$session where username='WATER10';alter system kill session'22,1';drop user water320000 cascade;

6. 查询用户记录最多的10条

select rownum, b.*  from (select d.client_id, count(d.client_id) cnt          from detail d         group by client_id         order by cnt desc) b where rownum <= 10

 7. 分析重复数据的个数

select * from (select client_id,submeter,count(*) cnt from meterhx group by client_id,submeter) where cnt > 1