Re: Idempotence and "Replication Insensitivity" are equivalent ?
From: Chris Smith <cdsmith_at_twu.net>
Date: Tue, 19 Sep 2006 08:47:14 -0600
Message-ID: <MPG.1f79b0e1bfb6ba8989717_at_news.altopia.net>
Date: Tue, 19 Sep 2006 08:47:14 -0600
Message-ID: <MPG.1f79b0e1bfb6ba8989717_at_news.altopia.net>
<pamelafluente_at_libero.it> wrote:
>
> Chris Smith ha scritto:
>
> > For example, AVG is an aggregate function because it is defined by
> > SUM(P) / COUNT(P), where SUM and COUNT can be defined as primitive
> > aggregate functions... but there is no function g that generates AVG
> > directly.
>
> consider also these "aggregate" functions:
>
> - range of values (difference between max and min)
This is MAX - MIN, so it is an aggregate function.
> - median
> - Any quantile
> - standard deviation
> - variance
These are not definable as aggregate functions.
> - Pearson's skewness
-- Chris SmithReceived on Tue Sep 19 2006 - 16:47:14 CEST