Eu mudei o script de Derek e funciona para mim agora:
UPDATE table1 AS t
INNER JOIN
(SELECT type,max(age) mage FROM table1 GROUP BY type) t1
ON t.type = t1.type AND t.age = t1.mage
SET name='HIGH'
UPDATE table1 AS t
INNER JOIN
(SELECT type,max(age) mage FROM table1 GROUP BY type) t1
ON t.type = t1.type AND t.age = t1.mage
SET name='HIGH'
