Aha i got it. thanks.
Why don't use a unified time zone Convention ?
If user is not particularly familiar with the document,
Maybe will feel confused.
At 2016-08-17 21:49:38, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>甄明洋 <zhenmingyang@yeah.net> writes:
>> this looks like, the sign plus and minus are inverted, i dont understand why?
>
>Time zone names follow the POSIX convention (plus is west of Greenwich).
>Timestamp I/O follows the ISO convention (plus is east of Greenwich).
>Aren't standards fun?
>
>See para starting "One should be wary ..." here:
>https://www.postgresql.org/docs/9.5/static/datatype-datetime.html#DATATYPE-TIMEZONES
>
> regards, tom lane
