Fran Fabrizio <ffabrizio(at)exchange(dot)webmd(dot)net> writes:
> I want to have a query that tells me whether or not the timestamp is
> within 'limit' minutes of the current time.
A poorly documented fact is that you can coerce an integer number of
seconds into a reltime, which can then be added to or subtracted from
a timestamp. So:
select tstamp > now() - reltime(limit*60) from ...
should do it.
regards, tom lane