WITH tbl1 AS (
    SELECT
        PF_CODE,
        100 * CAST(INP_YES AS real) / CAST((INP_YES+INP_NO+UNIDENTIFIED) AS  real) AS rate
    FROM    
        HOSPITALIZATION
)
SELECT
    PREFECTURE.PF_CODE AS '都道府県コード',
    PF_NAME AS '都道府県名',
    ifnull(ROUND(rate,1),0) AS '入院率' -- 都道府県毎の入院率
FROM
    PREFECTURE
LEFT JOIN
    tbl1
    ON PREFECTURE.PF_CODE = tbl1.PF_CODE
ORDER BY
    rate DESC, PREFECTURE.PF_CODE