Onsite interview anxiety: what to say when you don’t know an answer?

I have an onsite interview coming up, not virtual, and it’s been a while since I’ve interviewed in person. The recruiter said the coding portion could cover anything from data structures and algorithms to SQL, pandas, or even live model building, so I’m expecting there will be things I don’t know.

What’s really stressing me out is the idea of being in front of someone and blanking on a question. That feeling of just sitting there stuck feels embarrassing.

In that situation, what’s the best way to handle it? Is it better to say something like “Sorry, I can’t figure this out right now” or “I haven’t covered this topic before” and ask to move on?