嵌套if else语句[mysql]上的SQL语法错误

我有一个下面的sql函数，我试图使用嵌套的if-else语句

删除嵌套的“if”语句后，函数工作正常。但添加后，将显示错误

BEGIN
  DECLARE daysEntitled DECIMAL(4,2);
  DECLARE joinDate DATE;
  DECLARE dayOfMonth INT(4);
  SET joinDate = (SELECT join_date FROM users WHERE id = user);
  SET daysEntitled = TIMESTAMPDIFF(MONTH, joinDate, currentDate);
  IF YEAR(joinDate) = YEAR(currentDate) THEN
    SET currentDate = DATE_FORMAT(currentDate,'%Y-12-31');
    SET daysEntitled = TIMESTAMPDIFF(MONTH, joinDate, currentDate);
    SET dayOfMonth = CAST(DAY(joinDate) AS UNSIGNED);   

****** On adding this block ********

    IF dayOfMonth <= 15 THEN
       SET daysEntitled += 1.00;
    ENDIF;

****** On adding this block ********

  ELSEIF YEAR(joinDate) < YEAR(currentDate) THEN    
    SET daysEntitled = 8.00;    
  ELSEIF YEAR(joinDate) > YEAR(currentDate) THEN
    SET daysEntitled = 12.00;   
  ELSE
    SET daysEntitled = 4.00;  
  END IF;
  RETURN daysEntitled;
END

代码似乎很好。我不知道出了什么问题。

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非常感谢您的帮助。谢谢。

在MySQL中使用嵌套的IF语句没有什么错。我认为问题在于您试图增加变量的方式：

SET daysEntitled += 1.00;
                 ^^ not allowed

请改用此代码：

IF dayOfMonth <= 15 THEN
   SET daysEntitled = daysEntitled + 1.00;
ENDIF;

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MySQL说：1064-您的SQL语法有错误；检查与您的MariaDB服务器版本相对应的手册，了解正确的版本