使用單觸發

Question

我無法

與更新2臺一個觸發器，它給我一個錯誤附近「New.userid」更新多個表

CREATE TRIGGER userDownloads AFTER INSERT ON Downloads 
FOR EACH ROW 
UPDATE Project SET PROJECT_DOWNLOADS = PROJECT_DOWNLOADS + 1 WHERE PROJECTID = NEW.ProjectID, 
UPDATE User SET NO_OF_DOWNLOADS = NO_OF_DOWNLOADS + 1 WHERE USERID = NEW.UserID; 

Answer 1

你必須寫你的觸發器是這樣的：

DELIMITER // 
CREATE TRIGGER userDownloads AFTER INSERT ON Downloads 
FOR EACH ROW 
BEGIN 
    UPDATE Project SET PROJECT_DOWNLOADS = PROJECT_DOWNLOADS + 1 WHERE PROJECTID = NEW.ProjectID; 
    UPDATE User SET NO_OF_DOWNLOADS = NO_OF_DOWNLOADS + 1 WHERE USERID = NEW.UserID; 
END// 

請參閱它的工作here。

但是你確定需要觸發器嗎？爲什麼不在你的下載表上做COUNT？

SELECT ProjectID, COUNT(*) AS PROJECT_DOWNLOADS 
FROM Downloads 
GROUP BY ProjectID; 

SELECT UserID, COUNT(*) AS NO_OF_DOWNLOADS 
FROM Downloads 
GROUP BY UserID;