Select a list of unique values from a column using BDM Custom query

Hi

I would like to get distinct values for a column and am writing a custom query with a DISTINCT clause in BDM:-

Example: SELECT DISTINCT (C.NAME) FROM CUSTOMER C
Return Type :- Multiple (List)

While invoking the query via external API I am getting the error - Invalid Return type.

Any normal query with WHERE Clause works but looks like DISTINCT is creating an issue.

Please help.