mysql 中的event 在5.1及以上被支持，下面简单讲解下

1 启用
mysql> SET GLOBAL event_scheduler = ON;
关闭
SET GLOBAL event_scheduler = OFF;

2 注意的是event一旦创建后，则只有创建者对它有权限操作，而且5.1的event规定了
event的名称为64个字母大小写倒不敏感，event中不能再创建修改和删除其他event.

3 创建一个event
DELIMITER |

CREATE EVENT myevent
ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR
DO
BEGIN
UPDATE mytable SET mycol = mycol + 1;
END |

DELIMITER ;
这里注意用|来表示结束符号。这个事件是每隔1个小时更新数据表一次了
可以通过SHOW EVENTS\G 去看事件，如下
mysql> SHOW EVENTS\G
********************** 1. row **********************
Db: mysql
Name: myevent
Definer: dbuser@localhost
Time zone: SYSTEM
Type: ONE TIME
Execute At: 2011-10-26 20:24:19
Interval Value: NULL
Interval Field: NULL
Starts: NULL
Ends: NULL
Status: ENABLED
Originator: 0
character_set_client: utf8
collation_connection: utf8_general_ci

event在完成后会自动结束，除非显式地声明关闭，即
CREATE EVENT myevent
ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR
ON COMPLETION PRESERVE
DO
BEGIN
UPDATE mytable SET mycol = mycol + 1;
END |
使用on completion即可
event结束后，其实还留在数据库中，除非drop掉，即
DROP EVENT myevent;
如果要循环执行event,用every,即

CREATE EVENT myevent
ON SCHEDULE EVERY 1 HOUR
DO
BEGIN
UPDATE mytable SET mycol = mycol + 1;
END |

也可以指定开始和结束时间
CREATE EVENT myevent
ON SCHEDULE EVERY 1 HOUR
STARTS CURRENT_TIMESTAMP + INTERVAL 1 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 1 YEAR
DO
BEGIN
UPDATE mytable SET mycol = mycol + 1;
END |

当然，INTERVAL后可以跟day,year,month，hour,minutes,seconds等了
也可以更新event,比如

ALTER EVENT myevent
ON SCHEDULE EVERY 1 MONTH
STARTS '2011-12-01 01:00:00' |
更名：
ALTER EVENT myevent
RENAME TO yourevent;

在PHP代码中，也可以执行event,比如：
$query = "CREATE EVENT publish_:id

ON SCHEDULE AT FROM_UNIXTIME(:scheduleDate)

DO

BEGIN

UPDATE blog_posts SET status = 'published' WHERE id = :id;

END";

$stm = $db->prepare($query);

$stm->execute(array(":id" => $id, ":scheduleDate" => $scheduleDate));