Gregory Stark <stark@enterprisedb.com> writes:
> You can simulate such a plan with the subqueries I described but
> there's a bit more overhead than necessary and you need a reasonably
> efficient source of the distinct ids.
Yeah, that seems like the $64 question. If you have no better way of
finding out the set of ID values than a seqscan, then there's no point
in trying to optimize the min/max accumulation ...
regards, tom lane