mysql - 如何更新触发器中的多个表和字段？

Question

我有以下架构：SQL Fiddle。

触发器正在更新articles.votes 字段。我还需要使用与更新articles.votes 字段相同的公式来更新members.points 字段和memberslifetime_points 字段。我怎么做？

Answer 1

你在找这个吗？

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 ;

这是SQLFiddle演示