Re: [SQL] Howto to force NULL rows at the bottom ?

> I am not sure how we can resolve this.  btree cannot easily work
> differently than it does --- we could make either choice for where nulls
> appear in the index, but once we've done that we have no real choice
> about what ORDER BY on the index will do, in either direction.  So
> it seems that we really do need to make nulls sort differently in
> ASC and DESC sorts.  But the explicit-sort routine has no idea whether
> ASC or DESC is involved ... indeed can't, because we may have a
> "USING operator" clause in there and no ASC or DESC anywhere.  Shall
> explicit-sort try to guess whether the operator it's given represents
> the fore or aft direction of a btree index?  The operator might not be
> one that is btree-indexable at all, so I don't see how that can work.

We are pretty cheezy about using > and < for ORDER BY.  Any chance to
look up the actual comparison symbol from the cache and do something
based on "<" or ">"?  Do we have a pg_operator oid or something else
there?  If it is not one of those, we can just order them
however we want to.

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