Question

I inherited MYSQL database that has lots of tables with data like

CREATE TABLE IF NOT EXISTS `ejl_registration` (   `id` int(11) NOT NULL auto_increment,   `team_id` int(11) default NULL,   `start_date` date default NULL,   `end_date` date default NULL,   PRIMARY KEY  (`id`), ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=88668 ; 

start_date and end_date should have values like:

• 2007-1-5, 2007-12-31
• 2008-1-1, 2008-12-31
• 2009-1-15,2009-12-31

But some of those en_date fields are either NULL or 0000-00-00. Is there a ways to have single query to update all those invalid en_date fields and set their value to the end of the year equal to the year of start_date

Answer 1

Try this (please double check, I have not tested the command):

UPDATE `ejl_registration` SET `end_date`= CONCAT(YEAR(`start_date`),'-12-31') WHERE `end_date` IS NULL OR `end_date` = '0000-00-00';