Null values in a calculated dimension

[#1]

Hi is there a way to drill down into the null values in a chart which uses a calculated dimension. I have a pie chart with the following dimension which picks out only the values labelled 'High' and 'Low'. I want to be able to drill into the rest of the data which doesnt have a TAX_BAND assigned.

=if(not wildmatch(TAX_BAND, '*Low*', '*High*'), null(), TAX_BAND) as NEW_TAX_BAND

[#2]

Thanks Sunny. This approach partially works. Let me clarify I have the following

TAX_BAND

Low

High

Medium

Top

It shows three chunks ie Low, High and Null. The issue is the 'Null' values are aggregated along with 'Medium' and 'Top' also. Only when you click into the null chunk does it then correctly drill into the values only for the nulls. To confirm I want 3 chunks in my pie chart - Low, High and Nulls. The 'Medium' and 'Top' should be effectively completely ignored

[sunny_talwar]

Try this:

=If(WildMatch(TAX_BAND, '*Low*', '*High*'), TAX_BAND, If(Len(Trim(TAX_BAND)) = 0, 'NULL'))