Select parts.number, parts.model, sum(parts_used.quantity_used) as used, ;
		 sum(parts_received.quantity_received) as received 
from parts 
	left outer join parts_used on parts.number = parts_used.number ;
	left outer join parts_received on parts.number = parts_received.number 
group by 1
into cursor parts_cr


The left outer join will remove some of the clutter.

Godfrey Nicholson
Ofek Technologies Ltd
Auckland
New Zealand