SELECT
    HOSPITALIZATION.PF_CODE AS 都道府県コード
    , PREFECTURE.PF_NAME AS 都道府県名
    , ROUND(100 * SUM(HOSPITALIZATION.INP_YES) / (SUM(HOSPITALIZATION.INP_YES) + SUM(HOSPITALIZATION.INP_NO) + SUM(HOSPITALIZATION.UNIDENTIFIED)), 2) AS 入院率
FROM
    HOSPITALIZATION
    
    LEFT OUTER JOIN
        PREFECTURE
    ON  
        HOSPITALIZATION.PF_CODE = PREFECTURE.PF_CODE
GROUP BY
    都道府県コード

ORDER BY
    入院率 DESC
    , 都道府県コード