Re: Why using "Group By"

"Mikito Harakiri" <mikharakiri_at_ywho.com> wrote in message news:SW6ca.19$wV5.61_at_news.oracle.com...
> "Bob Badour" <bbadour_at_golden.net> wrote in message
> news:kZ6ca.74$SL2.8198261_at_mantis.golden.net...
> > I am unfamiliar with the proposal you mention, but that is not the
result
> I
> > recall getting in any case.
>
> http://www.dbpd.com/vault/9805date.htm

Since I first observed the problem with sybase in 1994 four years before Date's article, I doubt the problem has anything to do with that particular article. And in any case, the result in sybase is not the same as the interpretation you suggested.

Further, having just re-read the article, I do not see where Date proposed any such thing.

> > > For syntactically correct "group by" (when the select column list is a
> > > subset of "group by" list) rewritten the results are identical.
> >
> > Except that the only purpose of this is to destroy logical identity. Is
> this
> > as good as maintaining logical identity? I think not.
>
> What is logical identity, that you refer to so often?

Are you saying that you are unfamiliar with Codd's "12 Rules"? Or are you saying you are unfamiliar with the concept of identity? Or are you saying you are unfamiliar with the logical level of discourse?

> Do you mean that a
> relation where we have employee name in the first column, and the sum of
all
> salaries -- a constant -- in the second column would be a semantically
> invalid proposition?

No. Received on Thu Mar 13 2003 - 23:03:04 CET