我们如何创建一个在某个指定时间间隔后执行的 MySQL 一次性事件？

mysql> CREATE EVENT testing_event5 ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 MINUTE ON COMPLETION PRESERVE DO INSERT INTO event_message(message,generated_at) Values('Hi',NOW());
Query OK, 0 rows affected (0.06 sec)

mysql> Select * from event_message;
+----+---------+---------------------+
| ID | MESSAGE | Generated_at        |
+----+---------+---------------------+
| 1  | Hello   | 2017-11-22 17:05:22 |
| 2  | Hi      | 2017-11-22 17:08:37 |
+----+---------+---------------------+
2 rows in set (0.00 sec)