alter event event_name on schedule scheduleon completion [not] preserve rename to new_event_name enable | disable do event_body
为了理解它，我们将举例说明如下 -
示例假设我们有一个事件，如下 -
mysql> create event hello on schedule every 1 minute do insert into event_messages(message, generated_at) values ('alter event testing', now());query ok, 0 rows affected (0.00 sec)mysql> select * from event_messages;+----+---------------------+---------------------+| id | message | generated_at |+----+---------------------+---------------------+| 1 | without preserve | 2017-11-22 20:32:13 || 2 | with preserve | 2017-11-22 20:35:12 || 3 | alter event testing | 2017-11-22 21:08:37 |+----+---------------------+---------------------+3 rows in set (0.00 sec)mysql> alter event hello on schedule every 2 minute;query ok, 0 rows affected (0.00 sec)
上述查询会将事件的时间表从 1 分钟更改为 2 分钟。下面的查询将更改事件的正文。
mysql> alter event hello do insert into event_messages(message,generated_at) values('altered',now());query ok, 0 rows affected (0.00 sec)mysql> select * from event_messages;+----+---------------------+---------------------+| id | message | generated_at |+----+---------------------+---------------------+| 1 | without preserve | 2017-11-22 20:32:13 || 2 | with preserve | 2017-11-22 20:35:12 || 3 | alter event testing | 2017-11-22 21:08:37 || 4 | alter event testing | 2017-11-22 21:09:15 || 5 | altered | 2017-11-22 21:11:15 |+----+---------------------+---------------------+5 rows in set (0.00 sec)
上面的结果集显示我们在2分钟后收到了更改的消息。
以上就是我们如何修改现有的 mysql 事件？的详细内容。