sql.sql

一些基本的sql经典语句,供大家学习和参考

---查询那些用户，操纵了那些表造成了锁机 
SELECT  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,all_objects o  WHERE l.sid = s.sid  AND l.id1 = o.object_id(+) 
AND s.username is NOT Null 
看锁阻塞的方法是 
SELECT (select username FROM v$session WHERE sid=a.sid) blocker, 
      a.sid, 
      'is blocking', 
      (select username FROM v$session WHERE sid=b.sid) blockee, 
      b.sid 
  FROM v$lock a, v$lock b 
WHERE a.block = 1 
  AND b.request > 0 
  AND a.id1 = b.id1 
  AND a.id2 = b.id2  
  
  -----获取系统信息： 
select SYS_CONTEXT('USERENV','TERMINAL') terminal, SYS_CONTEXT('USERENV','LANGUAGE') language, SYS_CONTEXT('USERENV','SESSIONID') sessionid, SYS_CONTEXT('USERENV','INSTANCE') instance, SYS_CONTEXT('USERENV','ENTRYID') entryid, SYS_CONTEXT('USERENV','ISDBA') isdba, SYS_CONTEXT('USERENV','NLS_TERRITORY') nls_territory, SYS_CONTEXT('USERENV','NLS_CURRENCY') nls_currency, SYS_CONTEXT('USERENV','NLS_CALENDAR') nls_calendar, SYS_CONTEXT('USERENV','NLS_DATE_FORMAT') nls_date_format, SYS_CONTEXT('USERENV','NLS_DATE_LANGUAGE') nls_date_language, SYS_CONTEXT('USERENV','NLS_SORT') nls_sort, SYS_CONTEXT('USERENV','CURRENT_USER') current_user, SYS_CONTEXT('USERENV','CURRENT_USERID') current_userid, SYS_CONTEXT('USERENV','SESSION_USER') session_user, SYS_CONTEXT('USERENV','SESSION_USERID') session_userid, SYS_CONTEXT('USERENV','PROXY_USER') proxy_user, SYS_CONTEXT('USERENV','PROXY_USERID') proxy_userid, SYS_CONTEXT('USERENV','DB_DOMAIN') db_domain, SYS_CONTEXT('USERENV','DB_NAME') db_name, SYS_CONTEXT('USERENV','HOST') host, SYS_CONTEXT('USERENV','OS_USER') os_user, SYS_CONTEXT('USERENV','EXTERNAL_NAME') external_name, SYS_CONTEXT('USERENV','IP_ADDRESS') ip_address, SYS_CONTEXT('USERENV','NETWORK_PROTOCOL') network_protocol, SYS_CONTEXT('USERENV','BG_JOB_ID') bg_job_id, SYS_CONTEXT('USERENV','FG_JOB_ID') fg_job_id, SYS_CONTEXT('USERENV','AUTHENTICATION_TYPE') 
authentication_type, SYS_CONTEXT('USERENV','AUTHENTICATION_DATA') 
authentication_data 
  from dual
  
  
  --获取两时间的相差豪秒数
select ceil((To_date('2008-05-02 00:00:00' , 'yyyy-mm-dd hh24-mi-ss') - To_date('2008-04-30 23:59:59' , 'yyyy-mm-dd hh24-mi-ss')) * 24 * 60 * 60 * 1000) 相差豪秒数 FROM DUAL;
--获取两时间的相差秒数
select ceil((To_date('2008-05-02 00:00:00' , 'yyyy-mm-dd hh24-mi-ss') - To_date('2008-04-30 23:59:59' , 'yyyy-mm-dd hh24-mi-ss')) * 24 * 60 * 60) 相差秒数 FROM DUAL;
--获取两时间的相差分钟数
select ceil(((To_date('2008-05-02 00:00:00' , 'yyyy-mm-dd hh24-mi-ss') - To_date('2008-04-30 23:59:59' , 'yyyy-mm-dd hh24-mi-ss'))) * 24 * 60)  相差分钟数 FROM DUAL;
--获取两时间的相差小时数
select ceil((To_date('2008-05-02 00:00:00' , 'yyyy-mm-dd hh24-mi-ss') - To_date('2008-04-30 23:59:59' , 'yyyy-mm-dd hh24-mi-ss')) * 24)  相差小时数 FROM DUAL;
--获取两时间的相差天数
select ceil((To_date('2008-05-02 00:00:00' , 'yyyy-mm-dd hh24-mi-ss') - To_date('2008-04-30 23:59:59' , 'yyyy-mm-dd hh24-mi-ss')))  相差天数 FROM DUAL;
--获取两时间月份差
select (EXTRACT(year FROM to_date('2009-05-01','yyyy-mm-dd')) - EXTRACT(year FROM to_date('2008-04-30','yyyy-mm-dd'))) * 12 + 
       EXTRACT(month FROM to_date('2008-05-01','yyyy-mm-dd')) - EXTRACT(month FROM to_date('2008-04-30','yyyy-mm-dd')) months
from dual;
--获取两时间年份差
select EXTRACT(year FROM to_date('2009-05-01','yyyy-mm-dd')) - EXTRACT(year FROM to_date('2008-04-30','yyyy-mm-dd')) years from dual;