How do I log each users time session on a website where my users are stored in an SQL Database?

Bare with me as I am a noob when it comes to this (in the process of learning :D) I have a basic website made with html/css/php. There is a login page that requires a username and password to access all other areas of the website. The users are stored in a MySQL Database (fields: username, password, store, etc). I need/want to be able to view when the user logged in and how long that particular user was logged in for. I need a simplified way to show this data to someone who would not have access to the cpanel. Sorry for such a vague question, feel free to abuse me and ask for more info and I will reply with what's needed and asked of. EDIT: Sorry I would like to re-phrase what I've asked for as I think having every individual login sessions would make this log quite too much. What I need more accurately would be: How many times they logged in for the month Average duration of logins for the month Example: User A has logged in the website 200 times this month User A session duration each visit on average 5 minutes Sorry for the confusion. The examples above would be the data needed. Thanks in advanced.