how to build this query ??? Please help !!!

Hello there

I have a problem, building a query. Who can help ?
I use postgreSQL 7.0.3.

Thanks for any help and suggestions ... jr

orders
a_nr ¦ product ¦ state
-----------------------------
11   ¦ tp      ¦ aaaa
12   ¦ fi      ¦ bbbb
13   ¦ tp      ¦ cccc
14   ¦ ok      ¦ eeee
15   ¦ dm      ¦ aaaa

cylinders
z_a_nr   ¦     z_status
------------------------------
11     ¦  zdr
11     ¦  zdr
12     ¦  zdr
12     ¦  zcu
13     ¦  zdr
13     ¦  zcu
13     ¦  zcu
13     ¦  zcr
15     ¦  zcu
15     ¦  zcu
15     ¦  zdr

I need a query for the following output :

a_nr   ¦  #cylinder #zdr #zcu #zcr product    state
----------------------------------------------------------------------
11        2         2    0    0    dm         aaaa
12        2         1    1    0    tp         aaaa
13        4         1    2    1    fi         bbbb
14        0         0    0    0    ok         eeee
15        3         1    2    0    dm         aaaa





============================================
PFISTER + PARTNER, SYSTEM - ENGINEERING AG
Juerg Rietmann
Grundstrasse 22a
6343 Rotkreuz
Switzerland

phone: +4141 790 4040
fax: +4141 790 2545
mobile: +4179 211 0315
============================================