SELECT a.PF_CODE AS `都道府県コード`,  a.PF_NAME AS `都道府県名`, ROUND(c.rate, 1) AS 入院率
FROM PREFECTURE as a, 
(
  SELECT sum(b.INP_YES) * 100.0 / (sum(b.INP_YES) + sum(b.INP_NO) + sum(b.UNIDENTIFIED)) as rate, b.PF_CODE
  FROM HOSPITALIZATION as b
  GROUP BY b.PF_CODE
) as c

WHERE a.PF_CODE = c.PF_CODE
ORDER BY c.rate DESC, a.PF_CODE