Question

I have created this trigger for automatically generating user codes like SDA0001, SDA0002…
I have just included the main statements between BEGIN and END. It is create BEFORE INSERT on table agent_mst

DECLARE max_id INT;

SET max_id=(SELECT MAX(agent_id_pk)+1 FROM `agent_mst`);
IF (max_id IS NULL) THEN
    SET max_id=1;
END IF;

SET 
NEW.date_added=NOW(), 
NEW.date_updated=NOW(),
NEW.agent_code = CONCAT('SDA', LPAD(max_id, 4,'0'));

The error it is giving is as below

MySQL said: #1064 – You have an error in your SQL syntax; check the
manual that corresponds to your MySQL server version for the right
syntax to use near ‘DECLARE max_id INT; SET max_id=(SELECT
MAX(agent_id_pk)+1 FROM agent_mst); ‘ at line 1

I am creating this Trigger using phpMyAdmin.

Any suggestion what is wrong going here?
Thanks in advance.

Answer 1

This should work:

DELIMITER $$

CREATE TRIGGER trigger_name BEFORE INSERT ON `agent_mst`
FOR EACH ROW 
BEGIN
    DECLARE max_id INT;

    SET max_id=(SELECT MAX(agent_id_pk)+1 FROM `agent_mst`);
    IF (max_id IS NULL) THEN
        SET max_id=1;
    END IF;

    SET NEW.date_added=NOW(),
        NEW.date_updated=NOW(),
        NEW.agent_code = CONCAT('SDA', LPAD(max_id, 4,'0'));

END $$

DELIMITER ;