MySQL automatically set created and lastupdated timestamps on columns

ALTER TABLE `tablename`
ADD COLUMN `created` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
ADD COLUMN `updated` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;

https://dev.mysql.com/doc/refman/5.6/en/timestamp-initialization.html

https://dev.mysql.com/doc/refman/5.6/en/data-type-defaults.html

Requires MySQL 5.6.5 or better