管理不同时区的数据

例句：

select current_date, sysdate from dual;

例句:

SELECT CURRENT_TIMESTAMP  
  FROM DUAL;

例句：

SELECT LOCALTIMESTAMP
  FROM DUAL;

例一：

SELECT EXTRACT(year FROM DATE '2011-05-17') "year", 
       EXTRACT(month FROM DATE '2011-05-17') "month", 
       EXTRACT(day FROM DATE '2011-05-17') "day" 
  FROM DUAL;

例二：

SELECT EXTRACT(day FROM dt2-dt1) "day", 
       EXTRACT(hour FROM dt2-dt1) "hour", 
       EXTRACT(minute FROM dt2-dt1) "minute", 
       EXTRACT(second FROM dt2-dt1) "second" 
FROM (SELECT TO_TIMESTAMP('2011-02-04 15:07:00',
                          'yyyy-mm-dd hh24:mi:ss') dt1, 
             TO_TIMESTAMP('2011-05-17 19:08:46',
                          'yyyy-mm-dd hh24:mi:ss') dt1 
      FROM DUAL);

例句：

SELECT FROM_TZ(TO_TIMESTAMP('19880719','YYYYMMDD'),
               'America/Sao_Paulo')
  FROM DUAL;

例句：

SELECT SYSDATE + TO_DSINTERVAL('1000:00:00') A
  FROM DUAL;

例句：

SELECT TO_TIMESTAMP('19880719','YYYYMMDD')
  FROM DUAL;

例句：

SELECT TO_TIMESTAMP_TZ('1988-07-19 07:10:10.12320', 
                       'YYYY-MM-dd HH24:MI:SS.FF') A
  FROM DUAL;

例句：

SELECT SYSDATE+TO_YMINTERVAL('01-13') A
  FROM DUAL;

例句：

SELECT TZ_OFFSET('America/New_York')
  FROM DUAL;