更新MySQL中的特定列后触发触发器 [英] Fire a trigger after the update of specific columns in MySQL

问题描述

在MySQL中，我想在特定列更新后触发触发器.

In MySQL, I want to fire a trigger after the update of specific columns.

我知道如何在Oracle和DB2中做到这一点:

I know how to do it in Oracle and DB2:

CREATE  TRIGGER  myTrigger
AFTER UPDATE of myColumn1,myColumn2 ... ON myTable
FOR EACH ROW
BEGIN
....
END

如何使用MySQL做到这一点?

How to do that with MySQL?

推荐答案

您无法在SQL中的特定列更新上触发.它是连续应用的.

You can't trigger on a particular column update in SQL. It is applied on a row.

您可以使用IF语句在触发器中添加列条件，如下所示:

You can put your condition for columm in your trigger with an IF statement, as below:

DELIMITER //
CREATE TRIGGER myTrigger AFTER UPDATE ON myTable
FOR EACH ROW
BEGIN
   IF !(NEW.column1 <=> OLD.column1) THEN
      --type your statements here
   END IF;
END;//
DELIMITER ;

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