SELECT
 HOS.PF_CODE as 都道府県コード
 ,PRE.PF_NAME as 都道府県名
 ,ROUND(100.0*ifnull(INP_YES,'0')/(ifnull(INP_YES,'0')+ifnull(INP_NO,'0')+ifnull(UNIDENTIFIED,'0')),1) as 入院率
FROM
 HOSPITALIZATION HOS
JOIN
 PREFECTURE PRE
ON
 HOS.PF_CODE = PRE.PF_CODE
ORDER BY
 入院率 DESC;