select a.PF_CODE as 都道府県コード,
       b.PF_NAME as 都道府県名,
       ROUND(a.INP_YES*100 / (a.INP_YES+a.INP_NO+a.UNIDENTIFIED)) as 入院率
  from HOSPITALIZATION a 
  inner join PREFECTURE b on (a.PF_CODE=b.PF_CODE)
  order by ROUND(a.INP_YES / (a.INP_YES+a.INP_NO+a.UNIDENTIFIED)) desc, a.PF_CODE