The TIMESTAMP data type is the only data type which is used to have MySQL automatically set the time when a row is inserted and/or updated. DATETIME columns cant do this.

We can define more than one TIMESTAMP column in a table, but only one TIMESTAMP column in a table can set to be automatically initialized and automatically updated.

We can use TIMESTAMP with 4 options as below:

1. Auto-initialization and auto-update: We want to make column to be initialized and updated automatically.

 `modifiedDate` TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

2. Auto-initialization only: We want to make column to be initialized automatically only.

 `modifiedDate` TIMESTAMP DEFAULT CURRENT_TIMESTAMP

3. Auto-update only: We want to make column to be updated automatically only.

  `modifiedDate` TIMESTAMP DEFAULT 0 ON UPDATE CURRENT_TIMESTAMP

4. We don't want to do anything.

 `modifiedDate` TIMESTAMP DEFAULT 0

Example: In the below example I've used TIMESTAMP on modifiedDate column.

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(45),
  `createdDate` DATETIME DEFAULT NULL,
  `modifiedDate` TIMESTAMP ON UPDATE CURRENT_IMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Hope this will help you :)