Hello,

the is something simplier but not corresponding to your needs
select substring( datefield from 1 for 10) from yourtable;
that returns something like
SUBSTRING
----------
2007-09-24

I know, this is not exactly what you expect but perhaps is it enough ;o)

an other way to do it would be to use:
select TO_CHARD(datefield,'YYYYMMDD) from yourtable;
using udf4ora found at http://perso.orange.fr/Udf4ORA/

or some other like F_GFORMATD or F_DATETOSTR from FreeAdhocUDF

Regards
PAscal