It’s all in the title ! 
I was surprised to discover that for now in baserow, we can only put either ORs either ANDs, all at the same level (and no NOTs), and this is very limiting for some of our needs.
Agreed on this being an important feature. One work around for now is you can:
- Make a formula which calculates true for the rows you want to keep
- Add a filter on the formula field instead
By using a formula you can arbitrarily nest and use the comparison operators and the or and and functions to describe exactly the filter you need. However the formula language probably can’t yet express some of the more complicated field filters, or it is harder to wrap your head around how to express them.
Hello @nigel, thank you for your quick response, and your useful suggestion !
Indeed, the workaround that you propose will probably work for the most technical users (like me 
), but less so for some of my colleagues, and apart from the fact that it goes a little against the “no code” spirit, the filters as they appear should make it possible to quickly and easily try various searches in the data (which is not the case with your workaround where you have to add fields just in order to be able to do more complex searches).
Do you know if this feature is in the roadmap ?