How to group null values in set analysis as an expression?

[#1]

Hi,

I found this post here, http://community.qlik.com/message/172382#172382 but its not answering my question, more a workaround.

How do I group null values in set analysis as an expression so I can be certain that all null values are being treated as a set.

I have data that has values which I can group into various sets and then the balance is null and I want to group that as well.

When its not a null value (e.g. the category is M then my code looks like this, and this works fine.

sum({$<wcGroup={M}>}smProd)  / sum({$<wcGroup={M}>}qty)

Now when the wcGroup field contents isnt M but its null how can I manage the set?

I tried syntax

sum({$<wcGroup={""}>}smProd) / sum({$<wcGroup={""}>}qty)

sum({$<wcGroup={null}>}smProd) / sum({$<wcGroup={null}>}qty)

sum({$<IsNull(wcGroup)>}smProd) / sum({$<wcGroup={""}>}qty) 

and nothing is correct syntax-wise.

Within set analysis how do I manage null values?

Thanks

[hic]

I haven't tried this myself, but I suspect that if you include the following statements in the script, you could test for a NULL value with normal SET syntax:

NullAsValue "wcGroup";

set NullValue='<NULL>';

HIC