Print custom message when there is no data in table return by kusto query

[itshemant09]

I am working on a dashboard, where in backend Kusto query are running and plot a graph on dashboard based on the results.

I am trying to print a custom message like,

| extend CustomColumn=iff(isempty(expectedExpiration),"Expiration data is not available for this ",expectedExpiration)

i tried isempty, isnull, isNaN function as well but I am not getting this custom message as an output.

Can you help in finding what is going wrong here or I am missing something?

[sloutsky]

Perhaps, it is better to ask this kind of question at StackOverflow, tag it with 'kql'. Please use datatable() to present your input data.
This repo is for KQL parser library.