SQL - Result consisted of more than one row

Question

I'm still trying to make my first function, it creates without any errors, but when I try to use it, it gives me error - ERROR 1172 (42000): Result consisted of more than one row

Here's the function -

CREATE FUNCTION kontakti2 (mainigais CHAR(3)) 
RETURNS CHAR(100) 
BEGIN 
DECLARE returnthis CHAR(100); 
SELECT CONCAT(Person.name, Person.lastName, Contacts.mobile, Contacts.email) 
FROM Person JOIN Contacts on Contacts.Person_ID = Person.ID 
JOIN ParentChild on ParentChild.parentID = Person.ID 
JOIN ChildGroup ON ChildGroup.Person_ID = ParentChild.childID 
WHERE ChildGroup.Group_ID = mainigais INTO returnthis; 
RETURN returnthis; 
END//

Here's table schema, just in case - http://www.imagesup.net/dm-713886347846.png

How can I get this function to display several rows?

Answer 1

MySQL无法从函数返回多行，因为它不支持SQL Server中的表值函数。