On Thu, 2009-10-29 at 09:37 +0000, Richard Huxton wrote: > There are cases where one time is genuinely unknown, and there we need > a null.
The semantics of a period with one side NULL require a more clear definition. I don't personally see a lot of utility in trying to support NULL semantics, but if we want to support it, it needs to be clearly defined. Does TSQL-2 offer any guidance here? > That's assuming we've got a guarantee > that from<=to for all periods. Of course. Except that means that a NULL on one side of a period is a little less unknown than other kinds of NULLs ;) Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers