# Re: SQL (was: Why using "Group By")

Date: Sat, 15 Mar 2003 00:59:31 -0500

Message-ID: <eNzca.78$Yp5.7615634_at_mantis.golden.net>

"Mikito Harakiri" <mikharakiri_at_ywho.com> wrote in message
news:1hvca.11$k63.50_at_news.oracle.com...

> "--CELKO--" <71062.1056_at_compuserve.com> wrote in message

*> news:c0d87ec0.0303141635.612e1522_at_posting.google.com...
**> > >>Do you have an example problem requiring recursion for which
**> > transitive closure provides no solution? <<
**> >
**> > The Ackermann function, for one:
**> >
**> > A(0, m) = m+1
**> > A(n+1, 0) = A(n, 1)
**> > A(n+1, m+1) = A(n, A(n+1, m))
**>
**> Aha, I remember this one
**>
**>
*

http://www.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=bdf69bdf.02010

> 70553.1dcb8788%40posting.google.com

*>
**> but could anybody provide more substantial reference?
*

Since A(n,m) = n + m + 1 | ( n in Integer, m in Integer, n >= 0, m >= 0 ), why do we need recursion for this function?

Don't get me wrong. I have no objection to recursion, per se. I am just curious where it is needed. Received on Sat Mar 15 2003 - 06:59:31 CET