I'm trying to set up a site with a search function that allows people to select several tags or cats or whatever from a list, and then see only posts that contain ALL of those tags, cats or whatever. I.E., if they choose "dogs, cats, bananas", they do not see posts that are only tagged "dogs, bananas" - they only see posts with all three.
I've found a lot of plugins and several posts that come oh so very close to the answer, but not quite. I found one closed thread here from three years ago where someone worked hard to write php for this, bu in the end, decided it just wasn't possible. I'm hoping something has changed.
I would even be open to a standalone solution that can query the WP database in its own way. That could be incorporated into a WP page, and WP would still be at the heart of everything.