The Postgres manual says:
The AT TIME ZONE construct allows conversions of time stamps to
different time zones.
I'd guess most people would think what's meant here is something like
"unit conversion", and that the timestamp value stays the same (much
like 2 feet becomes 24 inches when it's being "converted"). But:
# SELECT NOW() = NOW() AT TIME ZONE 'UTC';
?column?
----------
f
(1 row)
--
dave