title: Updating field value on MySQL table after 24 hours automatically
body: <p>I have a table that stores some sensitive information but I would like that information to change to NULL when it exceeds 24 hours. How can I do that? I have a column named "last_updated" and stores value like this "2014-02-26 16:25:58".</p>
  
  <p>How can I compare the last_updated value with the current time and if it exceeds 24 hours, the other field will change to "NULL". </p>
  
  <p>Should I put something like <code>UPDATE table SET info=NULL WHERE last_updated &gt; 24hour?</code> I don't know how to compare the last_updated when its 24 hours later.</p>
  
  <p>or is there a function inside MySQL to check automatically without running the query using phpmyadmin? </p>