Hi @Michal Hauzírek, thanks for having a look!
We found that the issue is caused by some inner joins GoodData when "listing" the dashboard filters values.
In Bastien’s screenshot, we see an "age" attribute coming from the "feedbacks" table. However, in our LDM, feedbacks are connected to another "tags" table through a many-to-many relationship via a "feedback_tag_rels" intermediate table.
Looking at the query generated when applying the "age" filter, we noticed that if "feedback_tag_rels" is empty, the filter returns no results. Even though "tags" aren’t directly used in the filter, I guess the inner joins are applied because of the ldm?
We found that filling the many-to-many table fixes the issue for us. I think we will create an "empty" tag and link all feedback rows not linked to another tag to this placeholder one, to ensure the filtering behaves as expected. It is not pretty but it should work.
We are used to inner joins behavior when combining attributes and metrics in visualizations for example, but we weren’t expecting it from filters, especially since they don’t directly involve tags in our specific case.
Please let us know if our understanding make sense and if you have a better fix than the placeholder one. Thank you!