当我使用IS NOT NULL时无法创建MySQL TRIGGER [英] Can't Create MySQL TRIGGER when i use IS NOT NULL

问题描述

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，第一个帖子发布在这里.

First post here after hours of searching.

我正在尝试在更新预订表后使用触发器将其插入book_in_out中，但是我可以执行此操作，但是如果我更新bookName，触发器将尝试运行.

I'm trying to insert into book_in_out using trigger after updating booking table, I was able to do this but if I update bookName the trigger will try to run.

我只希望触发器仅在状态列更改时才运行. status列的默认值为NULL

I only want the trigger to run only when status column changes. default value for status column is NULL

以下是我不断收到的错误:

Below is the error i keep getting:

#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

推荐答案

您可以尝试

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 ;

这篇关于当我使用IS NOT NULL时无法创建MySQL TRIGGER的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！