A couple tips on the above:
With “intersect with”, you can modify it a few ways…
- If you want it to ignore empty inputs, then say :count has to be >0 and list a intersects with list b…
- You can specify the overlap by sticking a count at the end. Count >0 means at least 1 intersect. Or if you want all of the selected subjects to match, then set the :count to the # of selected subjects.
Also can read through these threads… lots of discussion on the topic: Stuck on how to make a complex search using check boxes
Regarding the original question at top (searching with an "or), note you can achieve this search without filters by combining multiple “do a search for” with the :merged function. This effectively creates the “or” and keeps the search server side (ie, faster).