获取给定时间戳和 TZ 名称的 TZ 缩写

Question

转换类型列后是否可以获得正确的 TZ 缩写timestamptz？

我是什么之后，SOF例子，是为了显示“2016年6月16日16：00-04：00”，在“美国/太平洋”时区与目标TZ缩写。我可以很容易地得到这个：

06/16/2016 01:00 pm

但我无法获得以下信息：

06/16/2016 01:00 pm PDT

一旦转换，timestamptz就变成timestamp without timezone，to_char说明符 'TZ' 变得毫无意义......

这是我尝试过的示例：

SELECT
    scheduled_dt                                                                           AS scheduled_dt
  , to_char(scheduled_dt, 'TZ')                                                            AS scheduled_dt_orig_tz  
  -- correct value, but missing TZ  
  , timezone('US/Pacific', scheduled_dt)                                                   AS schedules_dt_converted_tz
  , to_char(timezone('US/Pacific', scheduled_dt), 'MM/DD/YYYY HH:MI pm')                   AS scheduled_dt_converted_tz_localized
   -- after conversion TZ is lost
  , to_char(timezone('US/Pacific', scheduled_dt), 'MM/DD/YYYY HH:MI pm TZ')                AS scheduled_dt_converted_tz_localized_missing_tz
  -- with cast, wrong TZ is displayed 
  , to_char(timezone('US/Pacific', scheduled_dt)::timestamptz, 'MM/DD/YYYY HH:MI pm TZ')   AS scheduled_dt_converted_tz_localized_wrong_tz
FROM orders
LIMIT 5  

和示例输出：

"scheduled_dt","scheduled_dt_orig_tz","schedules_dt_converted_tz","scheduled_dt_converted_tz_localized","scheduled_dt_converted_tz_localized_missing_tz","scheduled_dt_converted_tz_localized_wrong_tz"
"2016-06-16 16:00:00-04","EDT","2016-06-16 13:00:00","06/16/2016 01:00 pm","06/16/2016 01:00 pm ","06/16/2016 01:00 pm EDT"
"2014-07-15 08:00:00-04","EDT","2014-07-15 05:00:00","07/15/2014 05:00 am","07/15/2014 05:00 am ","07/15/2014 05:00 am EDT"
"2012-11-27 10:15:00-05","EST","2012-11-27 07:15:00","11/27/2012 07:15 am","11/27/2012 07:15 am ","11/27/2012 07:15 am EST"
"2011-03-02 08:30:00-05","EST","2011-03-02 05:30:00","03/02/2011 05:30 am","03/02/2011 05:30 am ","03/02/2011 05:30 am EST"
"2016-02-12 14:23:09-05","EST","2016-02-12 11:23:09","02/12/2016 11:23 am","02/12/2016 11:23 am ","02/12/2016 11:23 am EST"

Answer 1

不，因为timestamptz（又名timestamp with time zone）并不是真正带有时区的时间戳，就存储的内容而言……您提供了时间戳和时区，在内部它只是存储为 UTC 值。

听起来基本上你应该将目标时区与时间戳一起存储在一个单独的字段中。