Hi Svein

> Solution b)
>

Wow, cross tabs in FireBird!!!

I must compliment you on your power on using CTE and frankly everytime I
see one from you I think I know how to use it the next time, but the
next time I am as lost as before. I just somehow cannot visualize it's
implementation. I know nothing can replace experience but is there a
layman's article to CTE that you or someone else can suggest.

Thanks and regards
Bhavbhuti