如何在触发器中更新多个表和字段？ [英] How to update multiple tables and fields in a Trigger?

问题描述

我具有以下架构： SQL小提琴。

触发器正在更新articles.votes字段。我还需要它来使用与更新article.votes字段相同的公式来更新members.points字段和members life_points字段。我该怎么办？

The trigger is updating the articles.votes field. I also need it to update the members.points field and the members lifetime_points fields with the same formula as updates the articles.votes field. How do I do that?

推荐答案

您在寻找这个吗？

DELIMITER $$
CREATE TRIGGER tg_ai_article_votes
AFTER INSERT ON article_votes
FOR EACH ROW 
BEGIN
  UPDATE articles
     SET votes = COALESCE(votes, 0) + 1
   WHERE id = NEW.article_id;
  UPDATE members
     SET points = COALESCE(points, 0) + 1,
         lifetime_points = COALESCE(lifetime_points, 0) + 1
   WHERE id = NEW.member_id;
END$$

CREATE TRIGGER tg_ad_article_votes
AFTER DELETE ON article_votes
FOR EACH ROW 
BEGIN
  UPDATE articles
     SET votes = COALESCE(votes, 0) - 1
   WHERE id = OLD.article_id;
  UPDATE members
     SET points = COALESCE(points, 0) - 1,
         lifetime_points = COALESCE(lifetime_points, 0) - 1
   WHERE id = OLD.member_id;
END$$
DELIMITER ;

这里是 SQLFiddle 演示

Here is SQLFiddle demo

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