纠正我在 mysql 触发器中的语法错误

Question

所以我尝试创建一个 mysql 触发器（在更新之前），它将检查员工表的哪个属性正在更新，我将向另一个表“Update_Message”添加一条语句，该语句指示更新的属性。这是我的代码：

DELIMITER //

CREATE TRIGGER update_col
BEFORE UPDATE
ON Employee FOR EACH ROW
BEGIN
    DECLARE Msg VARCHAR(100);
    SET Msg = '';
    IF NEW.eid!=OLD.eid THEN 
       SET Msg = CONCAT(Msg,"trying to update eid");
    ELSE IF STRCMP(NEW.ename,OLD.ename) = 0 THEN
       SET Msg = CONCAT(Msg,"trying to update ename");
    ELSE IF STRCMP(NEW.eaddress,OLD.eaddress) = 0 THEN
       SET Msg = CONCAT(Msg,"trying to update eaddress");
    ELSE
       SET Msg = CONCAT(Msg,"trying to update emonthlysalary");
    DELETE FROM Update_Message;
    INSERT INTO Update_Message (Message) VALUES (Msg);
END;
// 

它指出了一个语法错误：ERROR 1064 (42000): You have an error in your SQL syntax;检查与您的 MySQL 服务器版本相对应的手册，以获取正确的语法，以便在第 17 行的 '' 附近使用

请帮忙

Answer 1

阅读https://dev.mysql.com/doc/refman/8.0/en/if.html

IF search_condition THEN statement_list
    [ELSEIF search_condition THEN statement_list] ...
    [ELSE statement_list] 
END IF

您缺少必须完成此语句的END IF。