常用数据库语句（更新）

oracle：

SELECT * FROM v$lock;
SELECT * FROM v$sqlarea;
SELECT * FROM v$session;
SELECT * FROM v$process ;
SELECT * FROM v$locked_object;
SELECT * FROM all_objects;
SELECT * FROM v$session_wait;

--查看被锁的表 
select b.owner,b.object_name,a.session_id,a.locked_mode from v$locked_object a,dba_objects b where b.object_id = a.object_id;

--查看那个用户那个进程照成死锁
select b.username,b.sid,b.serial#,logon_time from v$locked_object a,v$session b where a.session_id = b.sid order by b.logon_time;

--查看连接的进程 
SELECT sid, serial#, username, osuser FROM v$session;

--查出锁定表的sid, serial#,os_user_name, machine_name, terminal，锁的type,mode
SELECT s.sid, s.serial#, s.username, s.schemaname, s.osuser, s.process, s.machine,
s.terminal, s.logon_time, l.type
FROM v$session s, v$lock l
WHERE s.sid = l.sid
AND s.username IS NOT NULL
ORDER BY sid;

--杀掉进程 sid,serial#
alter system kill session‘210,11562‘;

--查询oracle的连接数

select count(*) from v$session;

--查询oracle的并发连接数
select count(*) from v$session where status=‘ACTIVE‘;
--查看不同用户的连接数
select username,count(username) from v$session where username is not null group by username;

原文地址：https://www.cnblogs.com/xc-chejj/p/10730509.html