title: Alter table add new field "ON UPDATE CURRENT_TIMESTAMP"
body: <p>This is my table:</p>
  
  <pre><code>CREATE TABLE `megssage`(
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `name` varchar(256) DEFAULT NULL,
    `time_create` datetime DEFAULT NULL,
    PRIMARY KEY (`id`)
  ) ENGINE=MyISAM DEFAULT CHARSET=latin1
  </code></pre>
  
  <p>I would like to add new column as <code>time_updated</code> with default value "ON UPDATE CURRENT_TIMESTAMP". </p>
  
  <p>I tried this:</p>
  
  <pre><code>ALTER TABLE `megssage` 
     CHANGE `time_updated` `time_updated` TIMESTAMP NULL DEFAULT  ON UPDATE CURRENT_TIMESTAMP
  </code></pre>
  
  <p>But I am getting an error. Can someone help me?</p>