Why can a List field not be the "Group By" for a report, but can be the "Additional Group By"?

[Justin Abbott]

Fields of type List cannot be selected as the "Group By" on a bar report and I understand why. However, if you click the "Additional group by" button, fields of type List can be selected. Does anyone else see this same behavior or happen to know why? 

[sachin_namjoshi]

This is a bug on platform which allows list field in additional group by.

Also, documentation doesn't support list field in group by or stack by.

https://docs.servicenow.com/bundle/orlando-performance-analytics-and-reporting/page/use/reporting/task/add-additional-group-by-stack-by.html

REgards,

Sachin

[Brian Lancaster]

Because list fields will never be consistent.  Also I don't think it works when you put in the additional Group by field.  If I remember correctly there is a bug that allows things like list to be added to the additional group by.

[philhunt-nike]

It works fine as an additional group by.

[Ankur Bawiskar]

@Justin Abbott 

You cannot group by records based on a list type field which can hold multiple values. It supports fields that holds a single value.

As per docs additional group by is supported for list field; but not sure if it works fine or not

Add an additional group by or stack by

Regards
Ankur