MySQL定时器十例演示

企业开发 2018-09-15 11:48:46 阅读次数: 0

MySQL定时器十例演示

查看MySQL的版本号：

mysql> select version();
+------------+
| version()  |
+------------+
| 5.6.39-log |
+------------+
1 row in set (0.00 sec)

创建一个记录时间表

USE test;
CREATE TABLE test01 (timeline TIMESTAMP);

实例一：

查看MySQL的当前时间并且创建一个定时器，每20秒中插入一次当前的时间

select now();
CREATE EVENT e_test_insert
ON SCHEDULE EVERY 20 SECOND STARTS TIMESTAMP  '2018-09-15 09:20:00'
DO INSERT INTO test.test01 VALUES (CURRENT_TIMESTAMP);
mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 09:16:59 |
+---------------------+
1 row in set (0.00 sec)

mysql> CREATE EVENT e_test_insert
    -> ON SCHEDULE EVERY 20 SECOND STARTS TIMESTAMP  '2018-09-15 09:20:00'
    -> DO INSERT INTO test.test01 VALUES (CURRENT_TIMESTAMP);
Query OK, 0 rows affected (0.00 sec)

mysql>

查看MySQL当前时间：
mysql> select now();

等待20秒钟后，再执行查询成功。

mysql> select * from test01;
+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 09:01:07 |
| 2018-09-15 09:01:27 |
+---------------------+
2 rows in set (0.00 sec)

实例二：

创建一个定时器test01，当前时间2分钟后写入数据到test01_lastmonth表，并且清空test01表：

select now();
CREATE EVENT test01
ON SCHEDULE AT TIMESTAMP  '2018-09-15 09:30:00' + INTERVAL 2 MINUTE
do create table test.test01_lastmonth as select * from test.test01;TRUNCATE TABLE test.test01;

经测试
是新建了一个表test01_lastmonth，但是test01表没有被清空，并且一直在写入数据。说明上述的sql语句的写法是有问题的。

于是采用下面的写法是正确的。于是得出结论：采用下面的写法定时器是可以同时添加多条sql语句作为计划任务来执行的

delimiter $$
CREATE EVENT test02
ON SCHEDULE AT TIMESTAMP  '2018-09-15 09:40:00' + INTERVAL 2 MINUTE
COMMENT 'xiaowu create'
do 
    BEGIN
            create table test.test01_lastmonth as select * from test.test01;
            TRUNCATE TABLE test.test01;
    END $$
delimiter ;

此实例演示过程如下：

mysql> delimiter $$
mysql> CREATE EVENT test02
    -> ON SCHEDULE AT TIMESTAMP  '2018-09-15 09:40:00' + INTERVAL 2 MINUTE
    -> COMMENT 'xiaowu create'
    -> do 
    ->     BEGIN
    ->             create table test.test01_lastmonth as select * from test.test01;
    ->             TRUNCATE TABLE test.test01;
    ->     END $$
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;

此时查看新表还没被创建，旧表test01数据还没被清空

mysql>  select now();select * from test01_lastmonth;select * from test01;
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 09:41:54 |
+---------------------+
1 row in set (0.00 sec)

ERROR 1146 (42S02): Table 'test.test01_lastmonth' doesn't exist
+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 09:39:00 |
| 2018-09-15 09:39:20 |
| 2018-09-15 09:39:40 |
| 2018-09-15 09:40:00 |
| 2018-09-15 09:40:20 |
| 2018-09-15 09:40:40 |
| 2018-09-15 09:41:00 |
| 2018-09-15 09:41:20 |
| 2018-09-15 09:41:40 |
+---------------------+
42 rows in set (0.00 sec)

此时查看新表被创建，旧表test01数据被清空，并且已经插入一条数据
提示：旧表test01已经被清空了，但是之前的计划事件e_test_insert每20秒插入一条记录到test01表仍然在继续执行

mysql>  select now();select * from test01_lastmonth;select * from test01;
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 09:42:24 |
+---------------------+
1 row in set (0.00 sec)

+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 09:39:00 |
| 2018-09-15 09:39:20 |
| 2018-09-15 09:39:40 |
| 2018-09-15 09:40:00 |
| 2018-09-15 09:40:20 |
| 2018-09-15 09:40:40 |
| 2018-09-15 09:41:00 |
| 2018-09-15 09:41:20 |
| 2018-09-15 09:41:40 |
| 2018-09-15 09:42:00 |
+---------------------+
43 rows in set (0.00 sec)

+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 09:42:20 |
+---------------------+
1 row in set (0.00 sec)

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

再次总结测试实例二：

USE test;
CREATE TABLE test01 (timeline TIMESTAMP);
select now();
CREATE EVENT e_test_insert
ON SCHEDULE EVERY 20 SECOND STARTS TIMESTAMP  '2018-09-15 10:10:00'
DO INSERT INTO test.test01 VALUES (CURRENT_TIMESTAMP);
delimiter $$
CREATE EVENT test02
ON SCHEDULE AT TIMESTAMP  '2018-09-15 10:10:00' + INTERVAL 2 MINUTE
COMMENT 'xiaowu create'
do 
    BEGIN
            create table test.test01_lastmonth as select * from test.test01;
            TRUNCATE TABLE test.test01;
    END $$
delimiter ;
mysql> select now();select * from test01_lastmonth;select * from test01;
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 10:10:39 |
+---------------------+
1 row in set (0.00 sec)

ERROR 1146 (42S02): Table 'test.test01_lastmonth' doesn't exist
+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 10:10:00 |
| 2018-09-15 10:10:20 |
+---------------------+
2 rows in set (0.00 sec)

mysql>

此时新表已经创建并且旧表test01数据被清空：

mysql> select now();select * from test01_lastmonth;select * from test01;
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 10:12:00 |
+---------------------+
1 row in set (0.00 sec)

+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 10:10:00 |
| 2018-09-15 10:10:20 |
| 2018-09-15 10:10:40 |
| 2018-09-15 10:11:00 |
| 2018-09-15 10:11:20 |
| 2018-09-15 10:11:40 |
| 2018-09-15 10:12:00 |
+---------------------+
7 rows in set (0.00 sec)

Empty set (0.00 sec)

此时被清空的旧表test01 20秒后已经开始插入数据了
提示：旧表test01已经被清空了，但是之前的计划事件e_test_insert每20秒插入一条记录到test01表仍然在继续执行

mysql> select now();select * from test01_lastmonth;select * from test01;
+---------------------+
| now()               |
+---------------------+
| 2018-09-15 10:12:37 |
+---------------------+
1 row in set (0.00 sec)

+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 10:10:00 |
| 2018-09-15 10:10:20 |
| 2018-09-15 10:10:40 |
| 2018-09-15 10:11:00 |
| 2018-09-15 10:11:20 |
| 2018-09-15 10:11:40 |
| 2018-09-15 10:12:00 |
+---------------------+
7 rows in set (0.00 sec)

+---------------------+
| timeline            |
+---------------------+
| 2018-09-15 10:12:20 |
+---------------------+
1 row in set (0.00 sec)

实例三:定时每天的某个时间点来清空表test03

定时每天的上午10:45:00清空表test03

DROP EVENT IF EXISTS test03;
 CREATE  EVENT  test03
 ON SCHEDULE EVERY 1 day STARTS date_add(concat(current_date(), ' 10:45:00'), interval 0 second)
 ON COMPLETION PRESERVE ENABLE
 DO TRUNCATE TABLE test01;

定时每天的下午18:00:00清空表test03


DROP EVENT IF EXISTS test04;
 CREATE  EVENT  test04 
 ON SCHEDULE EVERY 1 day STARTS date_add(concat(current_date(), ' 18:00:00'), interval 0 second)
 ON COMPLETION PRESERVE ENABLE
 DO TRUNCATE TABLE test03;

实例四：定时每天的上午11:00:00清空表test01

CREATE EVENT test05
ON SCHEDULE  EVERY 1 day STARTS TIMESTAMP (current_date(),'11:00:00')
DO TRUNCATE TABLE test.test01;
查看创建事件调度器语句：
mysql> show create event test05\G
*************************** 1. row ***************************
               Event: test05
            sql_mode: STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION
           time_zone: SYSTEM
        Create Event: CREATE DEFINER=`root`@`localhost` EVENT `test05` ON SCHEDULE EVERY 1 DAY STARTS '2018-09-15 11:00:00' ON COMPLETION NOT PRESERVE ENABLE DO TRUNCATE TABLE test.test01
character_set_client: utf8
collation_connection: utf8_general_ci
  Database Collation: utf8_general_ci
1 row in set (0.00 sec)

实例五：

2018年7月20日12点整清空aaa表：

CREATE EVENT e1_test
ON SCHEDULE AT TIMESTAMP '2018-07-20 12:00:00'
DO TRUNCATE TABLE test.aaa;

实例六：

5天后开启每天定时清空aaa表：

CREATE EVENT e2_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;

实例七：
每天定时清空test表，5天后停止执行：

CREATE EVENT e3_test
ON SCHEDULE EVERY 1 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;

实例八：

5天后开启每天定时清空test表，一个月后停止执行：


CREATE EVENT e4_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 1 MONTH
DO TRUNCATE TABLE test.aaa;
[ON COMPLETION [NOT] PRESERVE]可以设置这个事件是执行一次还是持久执行，默认为NOT PRESERVE。

实例九：

每天定时清空test表(只执行一次，任务完成后就终止该事件)：

CREATE EVENT e5_test
ON SCHEDULE EVERY 1 DAY
ON COMPLETION NOT PRESERVE
DO TRUNCATE TABLE test.aaa;
[ENABLE | DISABLE]可是设置该事件创建后状态是否开启或关闭，默认为ENABLE。
[COMMENT ‘comment’]可以给该事件加上注释。

实例十：

修改事件(ALTER EVENT)
ALTER EVENT event_name
[ON SCHEDULE schedule]
[RENAME TO new_event_name]
[ON COMPLETION [NOT] PRESERVE]
[COMMENT 'comment']
[ENABLE | DISABLE]
[DO sql_statement]

将每天清空test表改为5天清空一次：

ALTER EVENT e_test
ON SCHEDULE EVERY 5 DAY;

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