查询oracle内部数据

1

--查看oracle现在连接者信息
 select username,machine, PROGRAM, count(username) from v$session
where username is not null 
group by username, machine, PROGRAM
order by username

 2

--查询数据库实例名[SID]
select * from v$instance;
select * from v$parameter2 t order by t.name ;

 3

--查询数据库版本信息
select * from v$version

 4

--查询oracle server端的字符集
select userenv('language') from dual

 5

---表空间使用情况
select a.tablespace_name,total,free,total-free used from   
( select tablespace_name,sum(bytes)/1024/1024 total from dba_data_files   
group by tablespace_name) a,   
( select tablespace_name,sum(bytes)/1024/1024 free from dba_free_space   
group by tablespace_name) b   
where a.tablespace_name=b.tablespace_name; 

 6

----查询数据表的列数
select count(1) from user_tab_columns where table_name=upper('jkda_101');

 7

--查询多少张表
--oracle某用户下所有表
select count(*) from dba_tables where owner in ('SYS');
--或者当前用户
select count(*) from user_tables;

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