Sql 比较随时间戳变化的字符

我试图比较postgresSQL中随时间戳变化的字符

我想获得当前时间之前的所有值，与字符变化时间戳进行比较

这个比较正确吗

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

时间戳（'2018-12-25T06:00:00+01:00'，'YYYY-MM-DD HH24:MI:SS'）不完全是这样。文本中有应该解析的时区值。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)