I don't see any option to export the members list. Can someone build an SQL query I can run in phpmyadmin to export the entire members list to a csv file? 

My goal is to review that list and modify the query to change the usergroup to "flagged" for any member who has not logged in within 2 years and has never posted. Once I have those in that usergroup, and do a final review, I would like to delete them all. 

Is this a reasonable approach to cleaning out old members?