Unique values in a dropdown of report parameter

Hello, If we have a selectable objects data source as it is available in reference selector, We can use a microflow to return group by values list. How to get unique values in the dropdown of report parameter widget?  
1 answers

I suspect you have multiple retrives and you give out a Union of them as an output. Try 1 retrive with a good xpath constraint. Then the database will not return double objects.