> 
> Summing is a bit harder; you may not be able to use a trick 
> like this at 
> all (until XPath 2).

If the magic value for empty nodes is zero, it's easy - just exclude
them from the set of nodes being summed using a filter:
sum(taxAmount[child::node()]).

Michael Kay
Software AG
home: Michael.H.Kay@xxxxxxxxxxxx
work: Michael.Kay@xxxxxxxxxxxxxx 
> 
> Cheers,
> Wendell
> 
> At 04:03 PM 5/24/2002, you wrote:
> >I want to find the numeric value of a node. If the node is 
> empty (e.g.:
> ><taxAmount/>) I want zero. I also want zero when applying 
> sum() to the 
> >same or a set of similar nodes.
> >Is there a solution to this problem other than setting a 
> variable, check 
> >the variable = NaN, return the variable or zero?
> 
> 
> ======================================================================
> Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
> Mulberry Technologies, Inc.                http://www.mulberrytech.com
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