Mysql create trigger if not exist

MySQLtrigger

I have a script that creates triggers,
I would like to run it multiple times and if a trigger already exist it needs to skip the creation part.

Is there a "create if not exist" in mysql triggers?

I tried :

    IF NOT EXISTS ((SELECT TRIGGER_NAME
        FROM information_schema.triggers
        WHERE TRIGGER_SCHEMA = 'xxx_admin' AND TRIGGER_NAME = 'test_AFTER_UPDATE')) 
        THEN
    CREATE DEFINER=`root`@`localhost` TRIGGER `xxx_admin`.`test_AFTER_UPDATE` AFTER UPDATE ON `test` FOR EACH ROW
        BEGIN
        INSERT INTO auditTest 
        select *, now() from test where id = NEW.id;
        END;
  END IF;

I get : syntex error " 'IF' is not valid input at this location

Best Answer

There is no CREATE TRIGGER IF NOT EXISTS

There is DROP TRIGGER IF EXISTS

You must execute the trigger's creation as follows:

USE xxx_admin
DELIMITER $$
DROP TRIGGER IF EXISTS test_AFTER_UPDATE $$
CREATE DEFINER=`root`@`localhost` TRIGGER `xxx_admin`.`test_AFTER_UPDATE`
AFTER UPDATE ON `test` FOR EACH ROW
BEGIN
    INSERT INTO auditTest 
    select *, now() from test where id = NEW.id;
END $$
DELIMITER ;

GIVE IT A TRY !!!

As for you error, using IF like that is not valid from the CLI.

Related Solutions

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You do not need a RETURN 1 because Trigger is a Stored Procedure, not a Stored Function.

If you want to break it on purpose, that's acceptable.

I wrote two posts about how to break a trigger midstream

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Try this:

CREATE /*!50017 DEFINER = 'root'@'localhost' */ TRIGGER `test`
BEFORE UPDATE ON `apply` 
FOR EACH ROW
BEGIN
    DECLARE dummy INT;

    IF NEW.cname = "hi" THEN          
        SET NEW.cname = "hello";
    ELSE
        SELECT no_such_column INTO dummy
        FROM information_schema.no_such_table;
    END IF;

END; $$

MySQL Trigger – How to Create Trigger for Update or Insert in Another Table

First, you need to specified when do you want to run the trigger inside the table. I've edited your trigger and use AFTER UPDATE and AFTER INSERT:

AFTER INSERT:

USE `TEST`;
DELIMITER $$
DROP TRIGGER IF EXISTS MEDICAMENTO.monthUpdateTriggerAI$$
USE `TEST`$$
    CREATE DEFINER = CURRENT_USER TRIGGER `TEST`.`monthUpdateTriggerAI` AFTER INSERT ON `TestTable` FOR EACH ROW
    BEGIN
    SET @COUNT=(SELECT COUNT(*) FROM TestTable2 WHERE (ItemId=NEW.ItemId AND Year=YEAR(NEW.Date) AND Month=MONTH(NEW.Date)));
    IF @COUNT=0 THEN
        INSERT INTO TestTable2 (ItemId,Year,Month,Open,Close,Increase ) VALUES 
        (NEW.ItemId , YEAR(NEW.Date), MONTH(NEW.Date),NEW.Value,NEW.Close,0.0); 
    ELSE
        UPDATE TestTable2 SET TestTable2.Close=NEW.Close AND Increase=(NEW.Close/(SELECT 
        Open FROM TestTable WHERE (Year=YEAR(NEW.Date) and Month=MONTH(NEW.Date)) LIMIT 1))
        WHERE (Year=YEAR(NEW.Date) and Month=MONTH(NEW.Date));
    END IF;
    END;
$$
DELIMITER ;

AFTER UPDATE:

USE `TEST`;
DELIMITER $$
DROP TRIGGER IF EXISTS MEDICAMENTO.monthUpdateTriggerAU$$
USE `TEST`$$
    CREATE DEFINER = CURRENT_USER TRIGGER `TEST`.`monthUpdateTriggerAU` AFTER UPDATE ON `TestTable` FOR EACH ROW
BEGIN

    UPDATE TestTable2 SET TestTable2.Close=NEW.Close AND Increase=(NEW.Close/(SELECT 
    Open FROM TestTable WHERE (Year=YEAR(NEW.Date) and Month=MONTH(NEW.Date)) LIMIT 1))
    WHERE (Year=YEAR(NEW.Date) and Month=MONTH(NEW.Date));

END;
$$
DELIMITER ;

Note: Be careful about the SELECT Open FROM TestTable WHERE (Year=YEAR(NEW.Date) and Month=MONTH(NEW.Date)), I've added a LIMIT 1 to avoid duplicate rows.

Change the database TEST.

You can also use ON DUPLICATE KEY on the two triggers execution.

You can get more information in the MySQL's documentation manual.