数据库SQL总结

将多张表（视图）的查询结果汇集到一起：union all
例如：

create view view_name as 
select A.a,A.b from A 
union all
select B.a,B.b from B

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获取当前日期

mysql：sysdate()
sqlserver：CONVERT(varchar,GETDATE(),120)

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Oracle查询死锁
—查询死锁进程

SELECT /*+ rule */ s.username,
decode(l.type,'TM','TABLE LOCK',
'TX','ROW LOCK',
NULL) LOCK_LEVEL,
o.owner,o.object_name,o.object_type,
s.sid,s.serial#,s.terminal,s.machine,s.program,s.osuser
FROM v$session s,v$lock l,dba_objects o
WHERE l.sid = s.sid
AND l.id1 = o.object_id(+)
AND s.username is NOT NULL and s.osuser='geekfly';

—关闭死锁进程

alter system kill session '624' ;