SQLNote

DELIMITER //

CREATE TRIGGER salaryDifference
AFTER INSERT ON customers
FOR EACH ROW
BEGIN
    DECLARE oldSalary INT DEFAULT 20000;
    DECLARE newSalary INT;
    DECLARE salaryDiff INT;

    SET newSalary=NEW.salary;
    SET salaryDiff=newSalary-oldSalary;

    INSERT INTO salaryLog(customerId, customerName, newSalary, oldSalary, salaryDiff)
    VALUES(NEW.ID, NEW.NAME, newSalary, oldSalary, salaryDiff);
END//

DELIMITER ;