PostgreSQL - 如何在不同时区呈现日期? [英] PostgreSQL - how to render date in different time zone?

问题描述

我的服务器在中部时间.我想使用东部时间呈现时间戳.

例如，我想将 2012-05-29 15:00:00 呈现为 2012-05-29 16:00:00 EDT.p>

我怎样才能实现它?

to_char('2012-05-29 15:00:00'::timestamptz at time zone 'EST5EDT', 'YYYY-MM-DD HH24:MI:SS TZ') 给出 2012-05-29 16:00:00(无区).

to_char('2012-05-29 15:00:00'::timestamp at time zone 'EST5EDT', 'YYYY-MM-DD HH24:MI:SS TZ') 给出 <代码>2012-05-29 14:00:00 CDT(错误).

这个可行，但它非常复杂，必须有一种更简单的方法:replace(replace(to_char(('2012-05-29 15:00:00'::timestamptz at time zone 'EST5EDT')::timestamptz, 'YYYY-MM-DD HH24:MI:SS TZ'), 'CST', 'EST'), 'CDT', 'EDT')

解决方案

关键是切换本地时区到想要显示的时区，在事务的持续时间内:

开始；将本地时区设置为EST5EDT"；select to_char('2012-05-29 15:00:00'::timestamp at time zone 'CDT','YYYY-MM-DD HH24:MI:SS TZ');结尾;

结果是:

<块引用>

2012-05-29 16:00:00 EDT

请注意，使用 set [local] timezone 需要使用完整的时区名称而不是缩写(例如，CST 不起作用).在 pg_timezone_names 视图中查找有效选择.

要在类似于 to_char() 调用的上下文中使用该方法，我相信这个函数可以完成这项工作:

创建函数 display_in_other_tz(in_t 时间戳，in_tzname 文本，in_fmt text) 返回文本作为$$宣布v 文本；save_tz 文本；开始在 save_tz 中显示时区；EXECUTE '将本地时区设置为' ||报价文字(in_tzname)；选择 to_char(in_t, in_fmt) INTO v;EXECUTE '将本地时区设置为' ||quote_literal(save_tz);返回 v;结尾;$$ 语言 plpgsql;

My server is in Central Time. I would like to render timestamps using Eastern time.

For instance, I would like to render 2012-05-29 15:00:00 as 2012-05-29 16:00:00 EDT.

How can I achieve it?

to_char('2012-05-29 15:00:00'::timestamptz at time zone 'EST5EDT', 'YYYY-MM-DD HH24:MI:SS TZ') gives 2012-05-29 16:00:00 (no zone).

to_char('2012-05-29 15:00:00'::timestamp at time zone 'EST5EDT', 'YYYY-MM-DD HH24:MI:SS TZ') gives 2012-05-29 14:00:00 CDT (wrong).

This one works, but it's so ridiculously complicated there must be an easier way: replace(replace(to_char(('2012-05-29 15:00:00'::timestamptz at time zone 'EST5EDT')::timestamptz, 'YYYY-MM-DD HH24:MI:SS TZ'), 'CST', 'EST'), 'CDT', 'EDT')

解决方案

The key is to switch the local timezone to the desired display timezone, for the duration of the transaction:

begin;
set local timezone to 'EST5EDT';
select to_char('2012-05-29 15:00:00'::timestamp at time zone 'CDT',
  'YYYY-MM-DD HH24:MI:SS TZ');
end;

The result is:

2012-05-29 16:00:00 EDT

Note that with set [local] timezone it is required to use full time zone names instead of abbreviations (for instance, CST would not work). Look up in the pg_timezone_names view for valid choices.

To use that method in a context similar to a to_char() call, I believe this function does the job:

CREATE FUNCTION display_in_other_tz(
      in_t timestamptz,
      in_tzname text,
      in_fmt text) RETURNS text
AS $$
DECLARE
 v text;
 save_tz text;
BEGIN
  SHOW timezone into save_tz;
  EXECUTE 'SET local timezone to ' || quote_literal(in_tzname);
  SELECT to_char(in_t, in_fmt) INTO v;
  EXECUTE 'SET local timezone to ' || quote_literal(save_tz);
  RETURN v;
END;
$$ language plpgsql;

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