Re: [GENERAL] Equivalence Classes when using IN

> If the only reason that is_simple_subquery() rejects subqueries with
> ORDER BY is due to wanting to keep the order by of a view, then
> couldn't we make is_simple_subquery() a bit smarter and have it check
> if the subquery is going to be joined to something else, which likely
> would destroy the order, or at least it would remove any guarantees of
> it.
>
> Something like the attached?

I dont know if it makes any difference that the ORDER BY is used in a
DISTINCT ON clause. In this case the ORDER BY is important.