MySQL函数在localhost中工作，但在上传到服务器时不存在

I have the following code for MySQL function

mysql_query("DROP FUNCTION IF EXISTS Review_Text;");
mysql_query("
CREATE FUNCTION Review_Text(rID INT)
RETURNS TEXT
READS SQL DATA
DETERMINISTIC
BEGIN
DECLARE Ans TEXT;
SET Ans = (SELECT `Text` FROM `data` WHERE `ID` = rID);
RETURN Ans;
END");

Which works beautifully on localhost. However, when I uploaded my files to online server the following error happens

FUNCTION mydatabase.Review_Text does not exist

Does anyone know why this happens and can it be fixed?