MySQL触发器IF语法错误

Question

我正在创建一些触发器（使用MySQL Workbench），但其中一个关于if语句出错。 这里是：

CREATE DEFINER = CURRENT_USER TRIGGER `mydatabase`.`transactions_AFTER_UPDATE` AFTER UPDATE ON `transactions` FOR EACH ROW
begin

if (old.idUser != new.idUser) then
    signal sqlstate '45000' set message_text = "Can't change transactions' initiator.";
end if;
declare oldAmountTokens integer;
SET @oldAmountTokens = (SELECT tokens from offers WHERE idoffer = old.idOffer);
declare newAmountTokens integer;
SET @newAmountTokens = (SELECT tokens from offers WHERE idoffer = new.idOffer);
declare diff integer;
SET @diff = @newAmountTokens - @oldAmountTokens;
UPDATE users SET tokens = users.tokens + @diff WHERE idUser = new.idUser;
end

MySQL Workbench告诉我

"missing 'end'" at line 6 （“ end if;”所在的位置） "missing 'end'" at line 6 ，

和phpMyAdmin告诉我

"#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 '' at line 5".

我真的很坚持，所以如果有人可以帮助我，我会非常高兴，我在网上搜索了IF语法，但是我没有发现任何错误...

Answer 1

好，问题解决了。

首先，我需要使用定界符来避免end if;附近的错误end if; 。

在接下来的错误，MySQL的要求declare报表中旁开始说，多亏了这个帖子我找到了答案。 谢谢 ！

Answer 2

尽管我要删除transactions后的单引号，但是您的触发代码对我来说还不错。 您是否有delimiter语句？

delimiter //

CREATE DEFINER = CURRENT_USER TRIGGER `mydatabase`.`transactions_AFTER_UPDATE`
    AFTER UPDATE ON `transactions` FOR EACH ROW
begin
    if (old.idUser <> new.idUser) then
        signal sqlstate '45000' set message_text = "Can't change transactions  initiator.";
    end if;
    declare @oldAmountTokens integer;
    SET @oldAmountTokens = (SELECT tokens from offers WHERE idoffer = old.idOffer);
    declare @newAmountTokens integer;
    SET @newAmountTokens = (SELECT tokens from offers WHERE idoffer = new.idOffer);
    declare @diff integer;
    SET @diff = @newAmountTokens - @oldAmountTokens;
    UPDATE users SET tokens = users.tokens + @diff WHERE idUser = new.idUser;
end//

delimiter ;