Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> The SQL window functions seem to require an ordering for most of their
> operations.
AFAICS, the entire concept of a "window" implies the input is ordered
in some way; what operations would they provide that don't require this?
> It is possible that that could be provided by a sort node in
> the execution plan.
Either sort or indexscan, but you'd certainly need one or the other.
regards, tom lane