-- Relative time with interval
DATE_SUB(NOW(), INTERVAL 25 HOUR)
 
-- Select all users that were updated in the last 24 hours.
SELECT * FROM users
WHERE users.updated > DATE_SUB(NOW(), INTERVAL 24 HOUR);
 
-- Select all users that were updated in the last 7 days.
SELECT * FROM users
WHERE users.updated > DATE_SUB(NOW(), INTERVAL 7 DAY);

http://www.apphp.com/index.php?snippet=mysql-calculate-relative-time-ago

Here you may find some useful snippets for calculating relative time for different purposes: to get info from a column within certain date, like the latest 7 days, to get time interval etc.

Calculate Relative Time Ago

sql

SQL