I have picked the following from the forums, couldn't find the actual link.
Please see if the following helps
1. group_users, groups ON GroupId = Id (Groups)
2. group_users, users ON User Id = Id (users)
3. groups, sites ON SiteId = Id (sites) AND SiteId (users) = Id (sites)
4, users, system_users ON System User ID = Id (System Users)
1 of 1 people found this helpful
Use the TS Users data source. Connect it to your PostgreSQL (extract if slow), drag Site Role to Rows, keep only Explorer / Explorer (can publish), drag Friendly Name or System Name to Rows alongside it.
Thank you Madhuri !
Thank you Matt this solved it !