mysql - 更新工资时计算并打印新旧工资差异的触发器

Question

Employee 表定义为 Employee(eno, ename, salary)。

写一个触发器，在更新工资时计算并打印新旧工资的差值。

我尝试了以下触发器。好像是计算差值。如何打印？

DELIMITER $$
CREATE TRIGGER t1
AFTER UPDATE ON employee
FOR EACH ROW
BEGIN   
    DECLARE sal_diff DECIMAL(10,2);
    IF eno = new.eno THEN
        IF (new.salary < old.salary) THEN
            SET sal_diff = old.salary - new.salary;
        ELSE
            SET sal_diff = new.salary - old.salary;
        END IF;
    END IF;
END $$
DELIMITER ;

Answer 1

类似的东西:

DELIMITER $$
CREATE TRIGGER t1
AFTER UPDATE ON employee
FOR EACH ROW
BEGIN   
    DECLARE sal_diff DECIMAL(10,2);
    IF new.salary < old.salary THEN
       set @sal_diff = old.salary - new.salary;
    ELSE
       set @sal_diff = new.salary - old.salary;
    END IF;
   -- Use  @sal_diff where you want it;
END $$
DELIMITER ;