SELECT
    T02.DISTRICT_NAME AS 都道府県名
  , T01.総人口
FROM (
SELECT
    SUBSTR(DISTRICT_CODE, -3, -2) AS T_DISTRICT_CODE
  , SUM(TOTAL_AMT) AS 総人口
FROM
    POPULATION
GROUP BY
    SUBSTR(DISTRICT_CODE, -3, -2)
HAVING
    T_DISTRICT_CODE <> ""
) AS T01
, POPULATION AS T02
WHERE
    T01.T_DISTRICT_CODE = SUBSTR(T02.DISTRICT_CODE, -3, -2)
AND T02.LVL = 2
ORDER BY
    総人口 DESC