I just want to say thank you so much for the tip! Like you, I wasted hours trying to solve this problem, only to finally come across this post and realize my carelessness.
I assumed there was no way to restore it, so I figured out my own solution: I imported an old backup I had of the database from two months ago, then use Google’s cache of the site to repost each of the missing posts. Time consuming, but a decent solution, nonetheless.
Hope this helps someone else!
The location in phpMyAdmin where I imported the file was actually not either of the two databases. I did not select a database before doing the import, so it apparently chose to overwrite Site 1’s tables by default.
