select POPU_TRANSITION.PF_CODE 都道府県コード,y2020.PF_NAME 都道府県名,POPU_TRANSITION.TOTAL_AMT as 総人口2015年,y2020.TOTAL_AMT as 総人口2020年,
round(cast(y2020.TOTAL_AMT as real) * 100/cast(POPU_TRANSITION.TOTAL_AMT as real),0) 人口増加率
from POPU_TRANSITION
inner join PREFECTURE
on POPU_TRANSITION.PF_CODE = PREFECTURE.PF_CODE

inner join

(select POPU_TRANSITION.PF_CODE,PF_NAME,TOTAL_AMT
from POPU_TRANSITION
inner join PREFECTURE
on POPU_TRANSITION.PF_CODE = PREFECTURE.PF_CODE
where SURVEY_YEAR = 2020) as y2020
on POPU_TRANSITION.PF_CODE = y2020.PF_CODE 

where POPU_TRANSITION.TOTAL_AMT <= y2020.TOTAL_AMT
and SURVEY_YEAR = 2015
order by 人口増加率 desc, 都道府県コード