DELIMITER $$
CREATE
TRIGGER `t_item_update` BEFORE UPDATE ON `items`
FOR EACH ROW
BEGIN
IF new.PCID <> old.PCID THEN
SIGNAL SQLSTATE 'HY000' SET MESSAGE_TEXT = 'PCID不允许修改';
END IF;
END;
$$
DELIMITER ;
列查询失败了: "CREATE TRIGGER `noupdate` AFTER UPDATE ON `items` FOR EACH ROW DELIMITER $$ CREATE TRIGGER `t_item_update` BEFORE UPDATE ON `items` FOR EACH ROW BEGIN IF new.PCID <> old.PCID THEN END IF; END; $$ DELIMITER ;"
MySQL 返回: #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 '$$ CREATE TRIGGER `t_item_update` BEFORE UPDATE ON `items` FOR EACH ' at line 1