比较随时间戳变化的字符

Question

我正在尝试比较PostgresSQL中随时间戳变化的字符。

我想获取当前时间之前与字符变化时间戳相比的所有值。

此比较是否正确？

WHERE to_timestamp('2018-12-25T06:00:00+01:00', 'YYYY-MM-DD HH24:MI:SS') < now()

Answer 1

不完全是。文字中存在时区值，应对其进行解析。比较：

select
    to_timestamp('2018-12-25T06:00:00+01:00', 'YYYY-MM-DD HH24:MI:SS') as "seems ok",
    to_timestamp('2018-12-25T07:00:00+02:00', 'YYYY-MM-DD HH24:MI:SS') as "but this is wrong!",
    to_timestamp('2018-12-25T06:00:00+01:00', 'YYYY-MM-DD HH24:MI:SS+TZH:TZM') as "ok",
    to_timestamp('2018-12-25T07:00:00+02:00', 'YYYY-MM-DD HH24:MI:SS+TZH:TZM') as "ok too"

        seems ok        |   but this is wrong!   |           ok           |         ok too         
------------------------+------------------------+------------------------+------------------------
 2018-12-25 06:00:00+01 | 2018-12-25 07:00:00+01 | 2018-12-25 06:00:00+01 | 2018-12-25 06:00:00+01
(1 row)