Bulk reassigning post author in specific forum, criteria
 

After importing a huge amount of 'threads' (actually reviews) on my friend's site, most of them were by default assigned to him as the author. We would like to change the author to a 'bot' account.

How could this be achieved by query?

We basically want to reassign the author "X" to "Y", in forum "A", for all of "X"s threads that have no replies. (E.g. His is the only post in the thread.)

Is there a simple enough query to run to do this?