Example of how to set automatic creation time and modification time in mysql

CREATE TABLE `course` (
 `course` varchar(255) DEFAULT NULL,
 `user` varchar(255) DEFAULT NULL,
 `score` int(11) DEFAULT NULL,
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `create_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT 'Creation time',
 `update_time` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT 'Update time',
 PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8;

-- Modify create_time to set the default time CURRENT_TIMESTAMP 
ALTER TABLE `course`
MODIFY COLUMN `create_time` datetime NULL DEFAULT CURRENT_TIMESTAMP COMMENT 'Creation time';

-- Add update_time and set the default time to CURRENT_TIMESTAMP. Set the update time to ON UPDATE CURRENT_TIMESTAMP. 
ALTER TABLE `course`
ADD COLUMN `update_time` datetime NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT 'Update time';