PostgreSQL更新时区偏移量

Question

有什么方法可以快速简便地纠正TIMESTAMP WITH TIME ZONE在错误的时区内意外输入的时区字段？

在我的情况下,以下记录错误地以UTC而不是美国/太平洋输入:

           t0           |           t1           |     what
------------------------+------------------------+---------------
 2011-06-01 13:00:00+00 | 2011-06-01 13:10:00+00 | recalibrating
 2011-06-01 13:10:00+00 | 2011-06-01 13:45:00+00 | verifying
 2011-06-01 13:45:00+00 | 2011-06-01 13:55:00+00 | FAULT

幸运的是,没有任何错误的记录跨越夏令时边界,所以UTC的2点可以简单地修正为太平洋2点.

Answer 1

UPDATE <table> SET <timestamptz_field> = (<timestamptz_field> AT TIME ZONE 'UTC') AT TIME ZONE '<correct_time_zone>';

Answer 2

有一些演员表,更重要的是at time zone操作员,它们对这类事物非常有用,例如:

test=#  select now(),
               now()::timestamp;

              now              |            now             
-------------------------------+----------------------------
 2011-06-27 14:32:04.169292+02 | 2011-06-27 14:32:04.169292
(1 row)

test=# select now() at time zone 'utc',
             (now() at time zone 'utc')::timestamp with time zone;

          timezone          |           timezone            
----------------------------+-------------------------------
 2011-06-27 12:32:28.430479 | 2011-06-27 12:32:28.430479+02
(1 row)