Monitoring Service: SQL statement to remove chat logs for a particular user

Can anyone help me with a SQL statement to properly remove all the chat logs for a specific user from the openfire db?

something like:

DELETE ofMessageArchive.*

FROM ofMessageArchive, ofConversation

WHERE ofMessageArchive.something = “john doe”

I am running Openfire 4.0.1 with monitoring service 1.5.0 with the embedded DB, HSQL Database Engine 1.8.0