Re: "Aggregate" operators
Date: Tue, 25 Apr 2017 14:16:35 +0200
Message-ID: <odnen3$211l$1_at_adenine.netfront.net>
On 25/04/2017 00:36, Erwin wrote:
> 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 ???
;)
Nicola
Received on Tue Apr 25 2017 - 14:16:35 CEST