SELECT
    AGE_CODE AS "年齢コード"
    ,AGE_NAME AS "年齢階層名"
    ,SP_TIME_5 AS "5時間未満"
    ,SP_TIME_6 AS "5時間以上6時間未満"
    ,SP_TIME_7 AS "6時間以上7時間未満"
    ,SP_TIME_8 AS "7時間以上8時間未満"
    ,SP_TIME_9 AS "8時間以上9時間未満"
    ,SP_TIME_9OVER AS "9時間以上"
FROM SLEEP_TIME_DTL
        NATURAL JOIN
    PREFECTURE
        NATURAL JOIN
    AGE_GRP

GROUP BY AGE_CODE
ORDER BY AGE_CODE
;