Mysql 加法触发器的右合成

代码：

当我想在phpmyadmin中添加触发器时，我得到错误：

# Triggers for table Likes->News

CREATE TRIGGER `TriggerUpdateNewsAfterInsertLikes` AFTER INSERT ON `Likes`
FOR EACH ROW
BEGIN 
UPDATE `News` SET 
`CountUpLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'up'),
`CountDownLikes` = (SELECT COUNT (*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'down'),
`CountFavorites` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `IsFavorite` = 'yes');
END;

#1064 - You have an error in your SQL syntax; check the manual 
that corresponds to your MySQL server version for the right syntax 
to use near '*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` 
AND `Type` = 'down'),
`CountFav' at line 8 

如果我使用

id

代替

*

我会得到错误：

# Triggers for table Likes->News

CREATE TRIGGER `TriggerUpdateNewsAfterInsertLikes` AFTER INSERT ON `Likes`
FOR EACH ROW
BEGIN 
UPDATE `News` SET 
`CountUpLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'up'),
`CountDownLikes` = (SELECT COUNT (*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'down'),
`CountFavorites` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `IsFavorite` = 'yes');
END;

#1064 - You have an error in your SQL syntax; check the manual 
that corresponds to your MySQL server version for the right syntax 
to use near '*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` 
AND `Type` = 'down'),
`CountFav' at line 8 

---

请告诉我如何正确添加触发器？

听起来难以置信，在mysql中，计数和（*）之间不能有空格：

在您的例子中，它位于第二个子查询中。将其更改为：

select count(*) -- OK
select count (*) -- syntax error!

---

这同样适用于

cast（…）

，这是一个语法错误：

cast（col为unsigned）

（注意

cast

和

（

）之间的空格。我可以告诉你，我花了大约一个小时寻找那颗小宝石

---

编辑 另一个错误可能是由于未更改分隔符，如果过程中有分号，则需要更改分隔符：

...
`CountDownLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'down'),
...

试试看：

DELIMITER //

CREATE TRIGGER `TriggerUpdateNewsAfterInsertLikes` AFTER INSERT ON `Likes`
FOR EACH ROW
BEGIN 
UPDATE `News` SET 
`CountUpLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'up'),
`CountDownLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `Type` = 'down'),
`CountFavorites` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = NEW.`NewsIdn` AND `IsFavorite` = 'yes');
END;//

DELIMITER ;

---

哦，对不起，我看不到，我认为

*

或

'

中的错误。非常感谢和抱歉。现在我得到第二个错误（

#1064-您的SQL语法有错误；请查看与MySQL服务器版本对应的手册，以获取第9行附近使用的正确语法。请参阅代码