Re: multiple paramters in aggregate function

<blockquote cite="mid:20090820122224.GA5532@merkur.hilbert.loc"
 type="cite">

    In other words, I have a conversion table of all different units. If
there is no conversion between 2 units (such as volume and area) then
the sum returns null.



Shouldn't that return NULL IOW unknown ?

Karsten


I am not familiar with returning unknown. I know that according to the
spec an aggregate should only return null if all of its values of the
aggregate are null. If there is a way to return unknown in a non-NULL
way, then that would be preferred.