Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> comp.databases.theory -> Re: Counting propositions

Re: Counting propositions

From: Paul G. Brown <paul_geoffrey_brown_at_yahoo.com>
Date: 14 Jun 2004 16:17:41 -0700
Message-ID: <57da7b56.0406141517.9cb7b7d@posting.google.com>


"x" <x-false_at_yahoo.com> wrote in message news:<40cd9b6a_at_post.usenet.com>...
> **** Post for FREE via your newsreader at post.usenet.com ****
>
> If tuples in a relational relation(ship) (or relvar) are propositions, what
> is the meaning of :
>
> select count(distinct *) as nr
> from <relvar>
>
> and the like ?

 Given that all relvars have a key, and assuming that your '*' is a macro that expands to 'all attributes' (don't matter what phase of query processing), then nr is going to equal the number of tuples in the relvar.

  In fact, there ought never be any need to do 'distinct' at all. Received on Mon Jun 14 2004 - 18:17:41 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US