SELECT
    HP.PF_CODE AS 都道府県コード,
    PF.PF_NAME AS 都道府県名,
    ROUND(
        -- 計算項目がINTEGER型なのでCAST関数でREAL型に変換して計算しています
        CAST(HP.INP_YES AS REAL)/
        CAST((HP.INP_YES + HP.INP_NO + HP.UNIDENTIFIED) AS REAL)
        * 100,
        1
        ) AS 入院率
FROM
    HOSPITALIZATION AS HP
    INNER JOIN PREFECTURE AS PF ON PF.PF_CODE = HP.PF_CODE
ORDER BY
    入院率 DESC,
    HP.PF_CODE ASC;