Question

我有程序：

    CREATE PROCEDURE channge_max_priority()
    BEGIN
      update feeds set max_post_priority =
        (
            select max(feed_posts.priority)
            from feed_posts
            where feed_posts.feed_id = feed_id
        )
        where feeds.id = feed_id;
    END

我想创建三个触发器：

      CREATE TRIGGER feed_post_after_test AFTER INSERT (And update and delete ) ON feed_posts
      FOR EACH ROW EXECUTE PROCEDURE change_max_priority();

程序正常工作，但是当我尝试启动触发器时 - 我收到错误：

Error in query (1064): Syntax error near 'PROCEDURE change_max_priority()' at line 2

Answer 1

您在名称程序中有一个nn个：

替换：

CREATE PROCEDURE channge_max_priority()

通过

CREATE PROCEDURE change_max_priority()

Answer 2

尝试更改update语句以使用连接，这应该有效：

update feeds 
set max_post_priority =  max(feed_posts.priority)
FROM feeds f
INNER JOIN feed_posts fp on feed_posts.feed_id = f.feed_id
Group BY f.feed_id

Answer 3

在mysql中，使用CALL执行过程：

CREATE TRIGGER feed_post_after_test AFTER INSERT (And update and delete ) ON feed_posts
      FOR EACH ROW CALL change_max_priority();

我不明白为什么你应该为每一行执行程序，整个feeds表在一个程序调用中更新。

也不确定过程中的最后where feeds.id = feed_id;（END之前）是否正确。

添加触发器时出现语法错误

3 个答案: