[mysql] MySQL set current date in a DATETIME field on insert

I have a 'created_date' DATETIME field which I would like to be populated with the current date upon insert. What syntax should I use for the trigger for this? This is what I have so far but it is incorrect.

CREATE TRIGGER set_created_date
BEFORE INSERT ON product
FOR EACH ROW BEGIN
SET NEW.created_date = now();

Using Now() is not a good idea. It only save the current time and date. It will not update the the current date and time, when you update your data. If you want to add the time once, The default value =Now() is best option. If you want to use timestamp. and want to update the this value, each time that row is updated. Then, trigger is best option to use.

1. http://www.mysqltutorial.org/sql-triggers.aspx
2. http://www.tutorialspoint.com/plsql/plsql_triggers.htm

These two toturial will help to implement the trigger.

DELIMITER ;;
CREATE TRIGGER `my_table_bi` BEFORE INSERT ON `my_table` FOR EACH ROW
BEGIN
    SET NEW.created_date = NOW();
END;;
DELIMITER ;

Since MySQL 5.6.X you can do this:

ALTER TABLE `schema`.`users` 
CHANGE COLUMN `created` `created` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP ;

That way your column will be updated with the current timestamp when a new row is inserted, or updated.

If you're using MySQL Workbench, you can just put CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP in the DEFAULT value field, like so:

http://dev.mysql.com/doc/relnotes/mysql/5.6/en/news-5-6-5.html