JSON: Expand nested columns with also NULL entries leads always to error

Hi DataInsights v-henryk-mstf 

I found now the solution. 

1. copy the existing query and removed all columns except Key and desired column.

2. Add a custom column in the new query and add code:

if Value.Is([issues.fields.customfield_20206], type list) 
then Text.Combine(List.Transform([issues.fields.customfield_20206], each [value]), "; ")
else null

3. Remove emtpy from that column.

Result is that what I want to have, coma separated values in one column: 

One last point I´m thinking about how to maybe add the step of removing the empty entries to the else-condition in the coding above.

Try to use the code by coping from the advanced editor after the last step, but this leads to an error.

Added to if-else condition like this

if Value.Is([issues.fields.customfield_20206], type list)

then Text.Combine(List.Transform([issues.fields.customfield_20206], each [value]), "; ")

else Table.SelectRows(#"Added Custom1", each [issues.fields.customfield_20206] <> null and [issues.fields.customfield_20206] <> "")

Error:

But this is a nice to have, in generall it works now. Thanks for your input.

BR primlchen