Kay-Uwe Genz <kug1977(at)web(dot)de> writes:
> Is this a bug or is this me mistake?
Yours I think. Type TIME WITH TIME ZONE stores a time of day
(from 00:00:00 to 23:59:59) plus a time zone (some offset east
or west of Greenwich --- I think we allow up to plus or minus
13 hours). I see nothing in the concept that would allow for
a negative local-time-of-day.
If you need a signed time-like datatype, maybe INTERVAL is closer
to what you're looking for.
regards, tom lane