在MySQL触发器AFTER Update语句中获取旧值 [英] Get OLD Value in MySQL Trigger AFTER Update Statement

问题描述

我有以下MySQL触发器

I have the following MySQL Trigger

SET @iUserId = OLD.LastChangedBy; 

IF NOT NEW.LastChangedBy <=> OLD.LastChangedBy THEN
    SET @iUserId = NEW.LastChangedBy;
END IF;

IF NOT NEW.BookingId<=> OLD.BookingId THEN
    INSERT INTO AuditTrail VALUES (UUID(),@iUserId,'UPDATE','Booking', OLD.BookingId,'BookingType ',OLD.BookingType ,NEW.BookingType ,NOW());
END IF;

这称为CREATE TRIGGER Booking_AUPD每行预订后更新

This is called as CREATE TRIGGER Booking_AUPD AFTER UPDATE ON Booking FOR EACH ROW

我遇到的问题是如何在AFTER UPDATE触发器中获取OLD字段值?

The problem I have is how can I get the OLD field value in a AFTER UPDATE trigger ?

推荐答案

关于错误的最可能解释

"There is no OLD row in on INSERT trigger"

是您正在执行创建AFTER INSERT触发器而不是创建AFTER UPDATE触发器的语句.

is that you are executing a statement that's creating an AFTER INSERT trigger, rather than creating an AFTER UPDATE trigger.

由于该行位于INSERT之前，所以无法从该行引用OLD值，原因是该行在INSERT之前不存在.

The reason that you can't reference OLD values from the row, as the row existed prior to the INSERT, is that the row did not exist prior to the INSERT.

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