title: PHP/MySQL Display time since user's last login
body: <p>I don't know what kind of value I should store in the database.</p>
  
  <p>I'm thinking I should do something like this, but I don't know how:</p>
  
  <p>Store the years, days, hours, minutes since a give date like 1/1/2000
  Then at another time I will compare that value against the current years, days, hours, and minutes since 1/1/2000.  Obviously, the difference between the two would be the time since the user's last login.</p>
  
  <p>I appreciate any help anyone can provide on this.
  Thanks in advance</p>