Question

我的时区是太平洋时间。我想根据地区将其转换为当地时间。下面是示例

          time                  region   
  2017-05-23 14:00:00           Central
  2017-05-23 14:00:00           Eastern 
  2017-05-23 14:00:00           Mountain

我在寻找什么

           time                  region               time_local
  2017-05-23 14:00:00           Central            2017-05-23 16:00:00
  2017-05-23 14:00:00           Eastern            2017-05-23 17:00:00
  2017-05-23 14:05:00           Mountain           2017-05-23 15:05:00

Answer 1

您可以加入时区系统视图以调整时间戳：

select 
  time,
  region,
  time - tz1.utc_offset + tz2.utc_offset
from Example ex
JOIN pg_timezone_names tz1
on tz1.name =  'US/Pacific'
JOIN pg_timezone_names tz2
on tz2.name = 'US/' || ex.region

Answer 2

假设您的“时间”列类型是正确的“带时区的时间戳”（也简称为“时间戳”）：

create table times (time timestamp with time zone not null, region text not null);

set timezone='US/Pacific';

insert into times (time, region) values
('2017-05-23 14:00:00','US/Central'),
('2017-05-23 14:00:00','US/Eastern'),
('2017-05-23 14:00:00','US/Mountain');

select *, time at time zone region as time_local from times;
          time          |   region    |     time_local      
------------------------+-------------+---------------------
 2017-05-23 14:00:00-07 | US/Central  | 2017-05-23 16:00:00
 2017-05-23 14:00:00-07 | US/Eastern  | 2017-05-23 17:00:00
 2017-05-23 14:00:00-07 | US/Mountain | 2017-05-23 15:00:00

如果您的时间栏是普通的时间戳，那么您需要先考虑对其进行更改，然后再疯狂。时间戳类型根本不表示时间戳，它表示某个地方将显示什么时钟，这取决于您身在何处，它在哪一天，在哪个国家/地区以及您的数据库客户端设置和当前环境以及之后的时间而不同。政客将来会改变时钟。不要走这条路。

Answer 3

您可以使用以下转换：

SET TIMEZONE TO 'US/Central';
SELECT now()::timestamp;
current_time
2018-07-25T14:01:50.608042Z

SET TIMEZONE TO 'US/Eastern';
SELECT now()::timestamp;
current_time
2018-07-25T15:01:50.608042Z

SET TIMEZONE TO 'US/Mountain';
SELECT now()::timestamp;
current_time 
2018-07-25T13:01:50.608042Z

SQL Fiddle Demo 1

或者使用：

SET TIMEZONE TO 'US/Central';
SELECT concat(current_date,' ',localtime) as current_time;
current_time
2018-07-25 14:10:57.962193

SET TIMEZONE TO 'US/Eastern';
SELECT concat(current_date,' ',localtime)  as current_time;
current_time
2018-07-25 15:10:57.962193

SET TIMEZONE TO 'US/Mountain';
SELECT concat(current_date,' ',localtime)  as current_time;
current_time
2018-07-25 13:10:57.962193

SQL Fiddle Demo 2

根据区域获取时区

3 个答案: