Is there a way to search transactions for vendors only in saved searches? I am doing that in SQL this way

transaction.entity IN (SELECT id FROM vendor)

Alternately you could join to vendor. What are you actually trying to achieve? Seems you could just filter down to transaction types that are for vendors.

No, I need to do it with saved searches now. I am generating a report that should show all credits and debits for vendors in a certain period. You can't filter down to transaction types because there are some transactions like journals that work for vendors and customers.

Vendor : Name/ID is not empty? Or formula {vendor.entityid} is not empty? Might be some trickiness depending on what lines you need (or want to exclude) for JEs/payable transactions, but that should at least get you all the transactions themselves I'd think.

It turns out that this is a bigger problem that I thought. Because even the way I was doing it in SQL

transaction.entity IN (SELECT id FROM vendor)

doesn't guarantee that you will get vendor transactions only, because some vendors have customer records with the same IDs.

You could add AND transaction.entity NOT IN (SELECT id FROM customer)

No, this won't do it, because vendors have the same IDs as their customer records.