oracle經常使用sql語句

計算表的行數count，sh爲oracle測試用戶，times爲該用戶下的表

select count(*) from sh.times;

從表student01的B列中，查找不重複的數據

select distinct B from student01;

複製表

create table time_hz tablespace xing1228 as select * from sh.times

將A列的數值加1，可是原始數據庫中不變

select a+1,b from student01;

select a,(a+1) bieming,b from student01;

查看當前用戶全部表名

select unique tname from col;

查看尚未提交的事務

select * from v$locked_object;

select * from v$transaction;

查看當前全部對象

select * from tab;

查看當前會話的SID和serial

SELECT Sid, Serial#

FROM V$session

WHERE Audsid = Sys_Context('USERENV', 'SESSIONID');

查詢當前時間

select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') from dual;

使用sqlplus計算

select 256*256 from dual;

經過受權方式來建立用戶

grant connect,resource to nlj identified by "123456";

用戶之間複製數據

建立一個表dep，dep列不能爲空

create table dep (dep number(2) not null, dname char(14), loc char(13));

找出未斷開的鏈接

select process,osuser,username,machine,logon_time ,sql_text

from v$session a,v$sqltext b

where a.sql_address=b.address;

查看錶空間名稱及大小（MB）

select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size

from dba_tablespaces t, dba_data_files d

where t.tablespace_name = d.tablespace_name

group by t.tablespace_name;

查看錶空間對應的物理文件位置及大小

select tablespace_name, file_id, file_name,round(bytes/(1024*1024),0) total_space

from dba_data_files

order by tablespace_name;

查看UNDO段

select segment_name, tablespace_name, r.status,(initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent,max_extents, v.curext CurExtent

From dba_rollback_segs r, v$rollstat v

Where r.segment_id = v.usn(+)

order by segment_name ;

查看錶空間使用狀況

select sum(bytes)/(1024*1024) as free_space,tablespace_name

from dba_free_space

group by tablespace_name;

查看oracle版本

Select version FROM Product_component_version

Where SUBSTR(PRODUCT,1,6)='Oracle';

查看數據庫建立時間和歸檔方式

Select Created, Log_Mode, Log_Mode From V$Database;

捕捉運行好久的SQL語句（TOP SQL）

select username,sid,opname,

round(sofar*100 / totalwork,0)  '%' as progress,time_remaining,sql_text

from v$session_longops , v$sql

where time_remaining <> 0

and sql_address = address and sql_hash_value = hash_value