# Re: Counting propositions

Date: Tue, 22 Jun 2004 09:39:32 -0700

Message-ID: <BsZBc.19$da4.142_at_news.oracle.com>

"x" <x-false_at_yahoo.com> wrote in message news:40d85df1$1_at_post.usenet.com...

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*>
**>
**> "Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message
**> news:DPYBc.18$da4.141_at_news.oracle.com...
**> >
**> > "Paul" <paul_at_test.com> wrote in message
**> > news:CFWBc.19053$NK4.3265189_at_stones.force9.net...
**> > > Isn't "select count(*)" a similar thing? You should explicitly name
*

the

> > > data columns you want. If you change the candidate keys it may change

*> > > the whole interpretation of the propositions. In which case it may no
**> > > longer be true that you want to count propositions.
**> >
**> > Count is unusual aggregate operator. Every other aggregate operator is
**> > associated with a binary operation. Indeed, the SUM is iterative
**> application
**> > of "+", the MAX is iterative application of "max(x,y)" (or CASE ...).
**> There
**> > are few exceptions like AVG, but they can be viewed as redundant (or at
**> > least less fundamental) operators.
**>
**> SUM(),MAX(),AVG() apply to a bag of values.
**>
**> > What operation COUNT is application of? The increment, of course. Unlike
**> the
**> > examples above, the increment is unary operation, so the COUNT shouldn't
**> > really have an argument!
**>
**> COUNT() apply to a bag of values.
*

SUM(a,b,c,d) = ((a + b) + c) + d

where brackets are inessential, as "+" is associative operators. Therefore, I'm talking about expressing an operation with variable number of arguments in terms of binary operation. Received on Tue Jun 22 2004 - 18:39:32 CEST