> there are many cases where the best solution are temporary tables.
> one could be: making a dynamic pivot?
>
> please do not answer with another question.

Why not? Many people come asking about a problem they think
is the solution - while in very many cases, those people are often
better of with a completely different solution. So, instead of asking
questions about the 'solution you think is right', ask questions
about your attempted solution AND describe your problem and
the reasons why you came to that [attempted] solution [that fails].

Martijn Tonies
InterBase Workbench - the developer tool for InterBase and Firebird
http://www.interbaseworkbench.com

Upscene Productions
http://www.upscene.com

"This is an object-oriented system.
If we change anything, the users object."