Question

I am trying to update a DATETIME field in a table. What I want for it is to always have three hours before it expires.

My current code is:

UPDATE mindcore_sessions
  SET session_time = DATE_ADD(session_time, INTERVAL 3 HOUR)
  WHERE session_id = '$sessionId';

An example value would be: 2013-02-11 00:00:00. If I run this query, it will change to: 2013-02-11 03:00:00. Which is correct. But, if it is run again, it changes to 2013-02-11 06:00:00 and so on.

What I want for it is to always be only three hours ahead. This is hard to explain, but I just want it to stay the same if it is run again. And if it is run again 1 minute later, I want it to increment by just one minute.

Sorry if the question is verbose, but I am utterly confused (and it is late!).

Thanks 🙂

Answer 1

Instead of adding three(3) hours to the last session_time, add three(3) hours to NOW():

update mindcore_sessions
set session_time = DATE_ADD(NOW(), INTERVAL 3 HOUR)
where session_id = '$sessionId';`