DELIMITER $$
 
DROP FUNCTION IF EXISTS Get_Age $$
 
CREATE FUNCTION Get_Age( dob DATE )
RETURNS CHAR(20)
BEGIN
    DECLARE years INT default 0;
    DECLARE months INT default 0;
    DECLARE days INT default 0;
    DECLARE age DATE;
 
    SELECT date_add('0001-01-01', interval datediff(current_date(),dob) day ) INTO age;
 
    -- Check that the age we're given is useful
    IF age is null or age = 0 or age = '0000-00-00' THEN
        RETURN age;
    END IF;
 
    SELECT YEAR(age) - 1 INTO years;
    SELECT MONTH(age)- 1 INTO months;
    SELECT DAY(age) - 1 INTO days;
 
    IF years THEN
        RETURN concat(years,'y ',months,'m');
 
    ELSEIF months THEN
        RETURN concat(months,'m ',days,'d');
 
    ELSE
            RETURN concat(days,' days');
    END IF;
 
END $$
 
DELIMITER ;