MySQL create event execution task

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 1、CREATE EVENT Create event Syntax

stay MySQL in , Can pass CREATE EVENT Statement to create an event , The syntax is as follows ：

CREATE EVENT [IF NOT EXISTS] event_name
    ON SCHEDULE schedule
    [ON COMPLETION [NOT] PRESERVE]
    [ENABLE | DISABLE | DISABLE ON SLAVE]
    [COMMENT 'comment']
    DO event_body;
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As can be seen from the above grammar ,CRATE EVENT A sentence consists of multiple clauses , The detailed description of each clause is shown in the following table .

Clause	explain
DEFINER	Optional Used to define the user who checks permissions when an event is executed
IF NOT EXISTS	Optional Used to determine whether the event to be created exists
EVENT event_name	Mandatory Used to specify the event name ,event_name The maximum length of is 64 Characters If not specified event_name, Default to current MySQL user name （ Case insensitive ）
ON SCHEDULE schedule	Mandatory Used to define the time and interval of execution schedule Indicates the trigger point
ON COMPLETION [NOT] PRESERVE	Optional Used to define whether an event is executed in a loop , That is, once or forever , The default is to execute once , namely NOT PRESERVE
ENABLE	DISABLE	DISABLE ON SLAVE	Optional , A property used to specify an event . among , keyword ENABLE Indicates that the event is active , That is, the scheduler checks whether the event must call ; keyword DISABLE Indicates that the event is closed , That is, the declaration of the event is stored in the directory , But it should not call the scheduler to check if ; keyword DISABLE ON SLAVE Indicates that the event is closed in the slave . If not specified above  3 Any one of the options , The default is ENABLE
COMMENT 'comment'	Optional , Comments used to define events
DO event_body	Mandatory Used to specify the code to be executed when the event starts , It can be anything that works SQL sentence 、 A stored procedure or an event scheduled for execution . If it contains more than one statement , You can use BEGIN..END Composite structure

2、 See if the event is on

show VARIABLES like 'event%';   --  if OFF, Then execute the following instructions 

--  Turn on 
SET GLOBAL event_scheduler = 1;
SET GLOBAL event_scheduler = ON;

--  close 
SET GLOBAL event_scheduler = 0;
SET GLOBAL event_scheduler = OFF;

--  View all events 
SHOW EVENTS;

--  Check the implementation of specific events 
SELECT * FROM information_schema.events WHERE EVENT_SCHEMA='test' ;   --  Query event details 
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3、 Create events and view execution data

 3.1  Create a table

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for one_data
-- ----------------------------
DROP TABLE IF EXISTS `one_data`;
CREATE TABLE `one_data`  (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT ' Primary key ID',
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL COMMENT ' name ',
  `sort_number` int(11) NULL DEFAULT NULL COMMENT ' Serial number ',
  `create_time` datetime(0) NULL DEFAULT NULL COMMENT ' Creation time ',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_unicode_ci COMMENT = ' Create events and add one piece of data per second ' ROW_FORMAT = Dynamic;

SET FOREIGN_KEY_CHECKS = 1;
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3.2  Create an event

--  If there are stored procedures e_test, Delete 
DROP PROCEDURE IF EXISTS e_test;

--  Create an event  
CREATE EVENT IF NOT EXISTS e_test
ON SCHEDULE EVERY '1' SECOND STARTS '2022-04-14 10:01:00'
ON COMPLETION  PRESERVE COMMENT ' every other 1 Add a piece of data in seconds '
DO INSERT INTO one_data(name, sort_number, create_time) VALUES (' name ', 2, NOW());


--  Create an event 
CREATE EVENT IF NOT EXISTS event_delete_de_records_7days ON SCHEDULE EVERY 1 DAY STARTS '2018-01-01 02:00:00'
ON COMPLETION  NOT PRESERVE  COMMENT ' Every morning 2 Click to execute once ' 
DO INSERT INTO one_data(name, sort_number, create_time) VALUES (' name ', 2, NOW());
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3.3  Event parameter description

--  Parameter name   explain 
-- EVENT_CATALOG  Event storage directory , In general , The value is  def, Modification is not recommended 
-- EVENT_SCHEMA  The database where the event is located 
-- EVENT_NAME  Event name 
-- DEFINER  The definer of the event 
-- TIME_ZONE  The time zone used by the event , The default is  SYSTEM, Modification is not recommended 
-- EVENT_BODY  In general , The value is  SQL, Modification is not recommended 
-- EVENT_DEFINITION  The content of the event , It can be specific  INSERT  etc.  SQL, It can also be a calling stored procedure 
-- EVENT_TYPE  Event type , This parameter is more important , Specify... When defining 
--  There are two values ：RECURRING  and  ONE TIME
-- RECURRING  It means that the execution will be repeated as long as the conditions are met ,RECURRING  Types of events are generally  NULL, Indicates the estimated execution time of the event 
-- ONE TIME  It will only call  EXECUTE_AT, in the light of  one-time  Events of type are valid 
-- INTERVAL_VALUE  in the light of  RECURRING  Events of type are valid , Indicates the execution interval length 
-- INTERVAL_FIELD  in the light of  RECURRING  Events of type are valid , Unit indicating execution interval , It's usually  SECOND,DAY  equivalence , Refer to the creation syntax 
-- SQL_MODE  Current event  SQL_MODE
-- STARTS  in the light of  RECURRING  Events of type are valid , Indicates the point in time at which an event starts executing , and  one-time  Of  EXECUTE_AT  The function is similar to .
--  by  NULL  When, it means that the execution starts as soon as the conditions are met 
-- ENDS  in the light of  RECURRING  Events of type are valid , Indicates the time point at which an event will not be executed , If  NULL  Just never stop 
-- STATUS  There are generally three values ,ENABLED、DISABLED  and  SLAVESIDE_DISABLED
-- ON_COMPLETION  There are only two values ,PRESERVE  and  NOT PRESERVE
-- CREATED  Event creation time 
-- LAST_ALTERED  The time when the event was last modified 
-- LAST_EXECUTED  The time when the event was last executed , If  NULL  Indicates that... Has never been executed 
-- EVENT_COMMENT  Comment information of the event 
-- ORIGINATOR  When the current event is created  server-id, Used for master-slave processing , such as  SLAVESIDE_DISABLED
-- CHARACTER_SET_CLIENT  The client character set at the time of event creation 
-- COLLATION_CONNECTION  Connection character verification rules when creating events 
-- DATABASE_COLLATION  Database character set verification rules at the time of event creation 
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3.4  Verify view data

SELECT * FROM `one_data`;

select lpad((select max(sort_number)+1 from one_data),3,'0')
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4、 Create a second event

4.1  Create table

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for interface_call
-- ----------------------------
DROP TABLE IF EXISTS `interface_call`;
CREATE TABLE `interface_call`  (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT ' Primary key ',
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ' The name of the interface ',
  `code` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT ' Unique code ',
  `all_value` int(10) NULL DEFAULT NULL COMMENT ' Total calls ',
  `today_value` int(10) NULL DEFAULT NULL COMMENT ' Number of calls today ',
  `create_time` datetime(0) NULL DEFAULT NULL COMMENT ' Creation time ',
  `update_time` datetime(0) NULL DEFAULT NULL COMMENT ' Update time ',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 22 CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = ' Health Report - Interface call data ' ROW_FORMAT = Dynamic;

SET FOREIGN_KEY_CHECKS = 1;
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4.2  Once every morning

CREATE DEFINER = `root`@`%` EVENT `interface_call`
ON SCHEDULE
EVERY '1' DAY STARTS '2021-10-12 00:00:00'
COMMENT ' The update is executed every morning, and the call volume today is zero '
DO UPDATE `interface_call` SET  `today_value` = 0, `update_time` = NOW();
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4.3  View event execution details

--  Check the implementation of specific events 
SELECT * FROM information_schema.events WHERE EVENT_SCHEMA='test' and EVENT_NAME='e_test';

-- test: Is the database name 
-- e_test:  Specific event name  
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