Re: "Aggregate" operators

[Quoted] Op maandag 24 april 2017 20:59:54 UTC+2 schreef Nicola:
> On 24/04/2017 20:06, Erwin wrote:
> > Looking for a *formal* definition of the term "aggregate" operator.
> >
> > The term is quite familiar and the one in common use to denote SQL
> > operators such as MIN, MAX, AVG that occur exclusively in connection
> > with some GROUP BY.
> >
> > However, "occur exclusively in connection with SQL GROUP BY" is rather
> > non-mathematical as a formal definition and so, is anyone around here
> > aware of something more rigorous as a *definition* of when some
> > operator is or is not an "aggregate" operator ?
>
> Off the top of my head, Klug's "Equivalence of Relational Algebra and
> Relational Calculus Query Languages Having Aggregate Functions" should
> have a formal definition.
>
> And have you checked Alice's book?
>
> Nicola

Whothe**** is Alice ???

(Sorry, couldn't resist. If you don't get it, look for a song by gompie. I'll check and pass the info. Thanks.) Received on Tue Apr 25 2017 - 00:36:19 CEST