select a.PF_CODE 都道府県コード, PF_NAME 都道府県名, round((ifnull(INP_YES,0) *100.0 /( IFNULL(INP_YES,0) + IFNULL(INP_NO,0) + IFNULL(UNIDENTIFIED,0))),1) 入院率
from HOSPITALIZATION a,
 PREFECTURE p
where a.PF_CODE = p.PF_CODE 
order by round((ifnull(INP_YES,0) *100.0 /( IFNULL(INP_YES,0) + IFNULL(INP_NO,0) + IFNULL(UNIDENTIFIED,0))),1) desc , length(a.PF_CODE),a.PF_CODE