Oracle将时区的TIMESTAMP转换为DATE

Question

我有时区的DB,+04:00 (Europe/Moscow)需要在Oracle 11g中将字符串格式转换YYYY-MM-DD"T"HH24:MI:SSTZH:TZM为DATE数据类型.

换句话说,我有一个字符串2013-11-08T10:11:31+02:00,我想将其转换为DATE数据类型(在本地数据库时区+04:00 (Europe/Moscow)).

对于字符串,2013-11-08T10:11:31+02:00我想要的转换应该返回DATE带有日期的数据类型2013-11-08 12:11:31(即使用时间的本地时区转换+04:00 (Europe/Moscow)).字符串的时区可能不同,+02:00上面的字符串只是示例.

我试图用TIMESTAMP数据类型做这个,但是时区转换没有成功.

Answer 1

to_timestamp_tz()function with at time zone子句可用于将字符串文字转换为timestamp with time zone数据类型的值:

SQL> with t1(tm) as(
  2    select '2013-11-08T10:11:31+02:00' from dual
  3  )
  4  select to_timestamp_tz(tm, 'yyyy-mm-dd"T"hh24:mi:ss TZH:TZM')
  5           at time zone '+4:00'         as this_way
  6       , to_timestamp_tz(tm, 'yyyy-mm-dd"T"hh24:mi:ss TZH:TZM')
  7           at time zone 'Europe/Moscow' as or_this_way
  8    from t1
  9  /

结果:

THIS_WAY                            OR_THIS_WAY
----------------------------------------------------------------------------
2013-11-08 12.11.31 PM +04:00       2013-11-08 12.11.31 PM EUROPE/MOSCOW

然后,我们使用cast()函数来生成date数据类型的值:

with t1(tm) as(
  select '2013-11-08T10:11:31+02:00' from dual
)
select cast(to_timestamp_tz(tm, 'yyyy-mm-dd"T"hh24:mi:ss TZH:TZM') 
         at time zone '+4:00' as date)   as this_way  
     , cast(to_timestamp_tz(tm, 'yyyy-mm-dd"T"hh24:mi:ss TZH:TZM') 
         at time zone 'Europe/Moscow' as date) as or_this_way
  from t1

This_Way             Or_This_Way 
------------------------------------------
2013-11-08 12:11:31  2013-11-08 12:11:31 

了解有关time zone子句和to_timestamp_tz()函数的更多信息.

Answer 2

SELECT
CAST((FROM_TZ(CAST(timezonefield AS TIMESTAMP),'GMT') AT TIME ZONE 'CET') AS DATE) 
FROM table;

将GMT中的时间戳转换为中欧时间的日期