Re: pg, mysql comparison with "group by" clause

On Thu, Oct 13, 2005 at 02:26:58PM -0400, Greg Stark wrote:
> Scott Marlowe <smarlowe(at)g2switchworks(dot)com> writes:
> > could run this query at the same time and get different data from the
> > same set and the same point in time.
>
> I'm pretty unsympathetic to the "we should make a language less powerful and
> more awkward because someone might use it wrong" argument.

That's not what Scott's saying. Scott is saying that the syntax
you're talking about is _formally wrong_. That's surely not "more
powerful", except in the sense that stepping on a land mine is more
powerful than many other ways you could shoot yourself in the foot.

> path. In an ideal world the user should be guaranteed that
> equivalent queries would always result in the same plan regardless
> of how they're written.

And again, I say it sounds like you're actually arguing for "the
optimiser needs to get better". Special-purpose, formally wrong
syntax is surely not better than making the optimiser get the right
syntax right every time, is it?

A

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