MySQL function definition - 'BEGIN' (begin) is not a valid input at this position - mysql

Question

I typed this up in verbatim from a textbook on MySQL.
There's a red X denoting an error on the line BEGIN with the text 'BEGIN' (begin) is not a valid input at this position.
The database used is View Ridge Gallery. Is there any obvious issues with the code?
DROP FUNCTION IF EXISTS InsertCustomerAndInterests;
DELIMITER $$
CREATE FUNCTION InsertCustomerAndInterests
(
newLastName Char(25),
newFirstName Char(25),
newAreaCode Char(3),
newPhoneNumber Char(8),
newEmail Varchar(100),
newNationality Char(30)
)
BEGIN
DECLARE varRowCount Int;
DECLARE varArtistID Int;
DECLARE varCustomerID Int;
DECLARE done Int DEFAULT 0;
DECLARE AristCursor CURSOR FOR
SELECT AristID
FROM ARTIST
WHERE Nationality=newNationality;
DECLARE continue HANDLER FOR NOT FOUND SET done = 1;
#Check to see if Customer already exists in datebase
SELECT Count(*) INTO varRowCount
FROM CUSTOMER
WHERE LastName = newLastName
AND FirstName = newFirstName
AND AreaCode = newAreaCode
AND PhoneNumber = newPhoneNumber
AND Email = newEmail;
#IF (varRowCount > 0 ) THEN Customer already exists
IF (varRowCount > 0 )
THEN
ROLLBACK;
SELECT 'Customer already exists';
END IF;
#IF (varRowCount = 0 ) THEN Customer does not exist.
#Insert new Customer data
IF (varRowCount = 0)
THEN
INSERT INTO CUSTOMER (LastName, FirstName, AreaCode, PhoneNumber, Email)
VALUES (newLastName, newFirstName, newAreaCode, newPhoneNumber, newEmail);
#Get new CustomerID surrogate key value
SET varCustomerID = LAST_INSERT_ID();
#Create intersection record for each appropriate Arist.
OPEN AristCursor;
REPEAT
FETCH ArtistCursor INTO varArtistArtistID;
IF NOT done THEN
INSERT INTO CUSTOMER_ARTIST_INT (ArtistID, CustomerID)
VALUES (varArtistID, varCustomerID);
END IF;
UNTIL done END REPEAT;
CLOSE ArtistCursor;
SELECT 'New customer and artist interest data added to database.'
AS InsertCustomerAndInterestsResults;
END IF;
END
$$
DELIMITER ;

Answer 1

You need to add return type before begin and must return value from the function.
DELIMITER $$
DROP FUNCTION IF EXISTS `InsertCustomerAndInterests`$$
CREATE FUNCTION `InsertCustomerAndInterests`(
newLastName CHAR(25),
newFirstName CHAR(25),
newAreaCode CHAR(3),
newPhoneNumber CHAR(8),
newEmail VARCHAR(100),
newNationality CHAR(30)
) RETURNS INT(11) # you missed return type here.
BEGIN
DECLARE done INT DEFAULT 0;
RETURN done; # must match with return type
END$$
DELIMITER ;

Answer 2

Since all functions need a return value and return type, you are missing the RETURNS clause after declaring your parameters. See CREATE FUNCTION