If you want show an article was posted "n hours n minutes and n seconds ago", you can use the TIMEDIFF(NOW(), pastTime) function as shown in the following tutorial exercise:

SELECT TIMEDIFF(NOW(), '2006-07-01 04:09:49') FROM DUAL;

06:42:58

SELECT TIME_FORMAT(TIMEDIFF(NOW(), '2006-06-30 04:09:49'),

'%H hours, %i minutes and %s seconds ago.') FROM DUAL;

30 hours, 45 minutes and 22 seconds ago.