MySQL定時器十例演示

查看MySQL的版本號：

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

創建一個記錄時間表

USE test;
CREATE TABLE test01 (timeline TIMESTAMP);

實例一：

查看MySQL的當前時間並且創建一個定時器，每20秒中插入一次當前的時間

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當前時間：
mysql> select now();

等待20秒鐘後，再執行查詢成功。

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

實例二：

創建一個定時器test01，當前時間2分鐘後寫入數據到test01_lastmonth表，並且清空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;

經測試
是新建了一個表test01_lastmonth，但是test01表沒有被清空，並且一直在寫入數據。說明上述的sql語句的寫法是有問題的。

於是採用下面的寫法是正確的。於是得出結論：採用下面的寫法定時器是可以同時添加多條sql語句作爲計劃任務來執行的

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 ;

此實例演示過程如下：

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 ;

此時查看新表還沒被創建，舊錶test01數據還沒被清空

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)

此時查看新表被創建，舊錶test01數據被清空，並且已經插入一條數據
提示：舊錶test01已經被清空了，但是之前的計劃事件e_test_insert每20秒插入一條記錄到test01表仍然在繼續執行

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)

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

再次總結測試實例二：

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>

此時新表已經創建並且舊錶test01數據被清空：

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)

此時被清空的舊錶test01 20秒後已經開始插入數據了
提示：舊錶test01已經被清空了，但是之前的計劃事件e_test_insert每20秒插入一條記錄到test01表仍然在繼續執行

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)

實例三:定時每天的某個時間點來清空表test03

定時每天的上午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;

定時每天的下午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;

實例四：定時每天的上午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;
查看創建事件調度器語句：
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)

實例五：

2018年7月20日12點整清空aaa表：

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

實例六：

5天后開啓每天定時清空aaa表：

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

實例七：
每天定時清空test表，5天后停止執行：

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

實例八：

5天后開啓每天定時清空test表，一個月後停止執行：


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]可以設置這個事件是執行一次還是持久執行，默認爲NOT PRESERVE。

實例九：

每天定時清空test表(只執行一次，任務完成後就終止該事件)：

CREATE EVENT e5_test
ON SCHEDULE EVERY 1 DAY
ON COMPLETION NOT PRESERVE
DO TRUNCATE TABLE test.aaa;
[ENABLE | DISABLE]可是設置該事件創建後狀態是否開啓或關閉，默認爲ENABLE。
[COMMENT ‘comment’]可以給該事件加上註釋。

實例十：

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]

將每天清空test表改爲5天清空一次：

ALTER EVENT e_test
ON SCHEDULE EVERY 5 DAY;

MySQL定時器十例演示

MySQL定時器十例演示

實例一：

實例二：

實例三:定時每天的某個時間點來清空表test03

實例四：定時每天的上午11:00:00清空表test01

實例五：

實例六：

實例八：

實例九：

實例十：

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