SELECT max_code.cd, max_code.VALUE
FROM
  (
    SELECT 'cd', pc.cd AS VALUE, pc.code FROM pc
    UNION
    SELECT 'hd', pc.hd, pc.code FROM pc
    UNION
    SELECT 'model', pc.model, pc.code FROM pc
    UNION
    SELECT 'price', pc.price, pc.code FROM pc
    UNION
    SELECT 'ram', pc.ram, pc.code FROM pc
    UNION
    SELECT 'speed', pc.speed, pc.code FROM pc
  ) AS max_code
WHERE max_code.code = (SELECT MAX(code) FROM pc)