Re: Question

On Sat, 2004-02-21 at 06:13, Chris Travers wrote:
> On Sat, 2004-02-21 at 09:13, David Costa wrote:
>
> > dead elephant ;) what about a cool one line postgresql query in lieu
> > of him ? could demonstrate the logic power of postgresql vs mysql and
> > others
> > anyone willing to share a nice one ?
>
> Hmmm.... Thinking of PostgreSQL vs MySQL vs. Firebird.....
>
> Unfortunately most of my complex queries are 8-10 lines long and use
> features such as subselects and UNION statements. Those will show the
> difference between MySQL and PostgreSQL, but should work in
> Interbase/Firebird.
>
> I am afraid the request to demonstrate the logic power of PostgreSQL in
> one line is sort of like asking for a proof to Fermat's Theorem in one
> double-spaced page and normal font size. If someone can do this, I will
> be quite impressed :-P

rbt=# select nspname, sum(relpages) from pg_class join pg_namespace n on
(relnamespace = n.oid) group by nspname, relnamespace having 2 > (SELECT
count(*) from pg_constraint where relnamespace = connamespace);

With some effort you might be able to get the above down to a single
line (shorter column names, etc.).

It takes the sum of pages used by relations in namespaces with a minimum
of 2 constraints.