MySql one time event never runs?
It appears to work for me

mysql&gt; SHOW CREATE TABLE t1\G
*************************** 1. row ***************************
       Table: t1
Create Table: CREATE TABLE `t1` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `data` varchar(255) NOT NULL DEFAULT '',
  `subdata` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

mysql&gt; CREATE EVENT Test1 ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 20 second ON COMPLETION PRESERVE ENABLE DO ALTER TABLE t1 DROP `subdata`;
Query OK, 0 rows affected (0.00 sec)

mysql&gt; SELECT SLEEP(20);
+-----------+
| SLEEP(20) |
+-----------+
|         0 |
+-----------+
1 row in set (20.01 sec)

mysql&gt; SHOW CREATE TABLE t1\G
*************************** 1. row ***************************
       Table: t1
Create Table: CREATE TABLE `t1` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `data` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)

mysql&gt; SHOW EVENTS;
+------+-------+----------------+-----------+----------+---------------------+----------------+----------------+--------+------+----------+------------+----------------------+----------------------+--------------------+
| Db   | Name  | Definer        | Time zone | Type     | Execute at          | Interval value | Interval field | Starts | Ends | Status   | Originator | character_set_client | collation_connection | Database Collation |
+------+-------+----------------+-----------+----------+---------------------+----------------+----------------+--------+------+----------+------------+----------------------+----------------------+--------------------+
| test | Test1 | root@localhost | SYSTEM    | ONE TIME | 2013-06-04 11:46:49 | NULL           | NULL           | NULL   | NULL | DISABLED |          0 | latin1               | latin1_swedish_ci    | utf8_general_ci    |
+------+-------+----------------+-----------+----------+---------------------+----------------+----------------+--------+------+----------+------------+----------------------+----------------------+--------------------+
1 row in set (0.00 sec)

mysql&gt; 


So my question is what does SHOW EVENTS display before and after the set runtime of the event?