I am confused with the three tables : ubbt_PRIVATE_MESSAGE_POSTS , ubbt_PRIVATE_MESSAGE_TOPICS , ubbt_PRIVATE_MESSAGE_USERS

How do I know if a user doesn't have any incoming PM and outgoing PM (except Admin's welcome message , Admin's ID = 2) ?
how to write such SQL message ?

BTW , the PMs in ubbt_USER_PROFILE.USER_TOTAL_PM is not synchronized with the real value , should it be considered as a bug ?

English is not my native language. I try my best to express my thought precisely. I hope you understand what I mean. If any misunderstanding results from culture gaps, I apologize first.