代码:
CREATE TRIGGER `TriggerUpdateNewsAfterChangeLikes` AFTER INSERT, UPDATE, DELETE ON `Likes`
FOR EACH ROW
BEGIN
UPDATE `News` SET
`CountUpLikes` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `Type` = 'up'),
`CountDownLikes` = (SELECT COUNT (*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `Type` = 'down'),
`CountFavorites` = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `IsFavorite` = 'yes');
END
当我进行查询时,在phpmyadmin中,我会出现错误:
#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 ' UPDATE ON `Likes`
FOR EACH ROW
BEGIN
UPDATE `News` SET
`CountUpLikes` = (' at line 1
请告诉我,为什么我会遇到此错误以及如何使其正确查询?
尝试这样的东西:
CREATE TRIGGER TriggerUpdateNewsAfterChangeLikes AFTER UPDATE ON Likes
FOR EACH ROW
BEGIN
UPDATE News SET
CountUpLikes = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `Type` = 'up');
UPDATE News SET
CountDownLikes = (SELECT COUNT (*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `Type` = 'down');
UPDATE News SET
CountFavorites = (SELECT COUNT(*) FROM `Likes` WHERE `NewsIdn` = OLD.`NewsIdn` AND `IsFavorite` = 'yes');
END;
不幸的是,MySQL不允许在同一触发器上进行多个事件。