MySQL触发IF语法错误

Question

我正在创建一些触发器（使用 MySQL Workbench），并且在其中一个中遇到了关于 if 语句的错误。这是：

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），

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".

我真的坚持这个，所以如果有人能帮助我，我会很高兴，我在网上搜索了 IF 语法，但我没有发现任何错误...

Answer 1

我觉得你的触发代码没问题，尽管我删除了 transactions 之后的单引号。你有 delimiter 个声明吗？

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 ;

Answer 2

好的，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。

对于下一个错误，MySQL 要求将 declare 语句放在开始的旁边，感谢这个 post 我找到了答案。谢谢！

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