Question

CREATE TRIGGER b_I_O AFTER UPDATE ON book
FOR EACH ROW
BEGIN
IF (OLD.status IS NOT NULL AND NEW.status IS NOT NULL AND NEW.status != OLD.status ) THEN
    INSERT INTO book_in_out (astatus, bid, time) VALUES(NEW.status, OLD.id, NOW());
END IF;
END;

经过数小时的搜索后，首先发布在这里。

我尝试在更新预订表后使用触发器插入book_in_out，我能够执行此操作，但如果我更新bookName，触发器将尝试运行。

我只希望触发器仅在状态列更改时运行。 status列的默认值为NULL

以下是我不断得到的错误：

#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 '' at line 5

Answer 1

尝试手动指定触发器的分隔符，这样就不会与BEGIN / END中使用的分号混淆，即

DELIMITER //
CREATE TRIGGER b_I_O AFTER UPDATE ON book
FOR EACH ROW
BEGIN
IF (OLD.status IS NOT NULL AND NEW.status IS NOT NULL AND NEW.status != OLD.status ) THEN
    INSERT INTO book_in_out (astatus, bid, time) VALUES(NEW.status, OLD.id, NOW());
END IF;
END;//

Answer 2

你可以试试这个

delimiter //
CREATE TRIGGER b_I_O AFTER UPDATE ON book
FOR EACH ROW
BEGIN
    IF (OLD.status IS NOT NULL AND NEW.status IS NOT NULL AND NEW.status != OLD.status ) THEN
        INSERT INTO book_in_out (`astatus`, `bid`, `time`) VALUES(NEW.status, OLD.id, NOW());
    END IF;
END;//
delimiter ;

当我使用IS NOT NULL时，无法创建MySQL TRIGGER

2 个答案: