How to obtain a group membership time evolution from login date / logout date table in mysql
a newcomer to mysql here: I have a members table with Name, login_date and logout_date columns. Name login_date logout_date John 2004-01-08 00:00:00 2004-01-10 00:00:00 Mary 2004-01-09 00:00:00 2005-05-31 00:00:00 Frank 2004-01-12 00:00:00 2005-11-08 00:00:00 Nancy 2004-01-12 00:00:00 2007-10-13 00:00:00 Louise…