with t as (select 1 p union select 2 p union select 3 p union select 4 p union select 5 p union select 6 p)

select 
   SV_YEAR ,PREFECTURE,KIND,sum(AMT) AMT
from
(
select 
    SURVEY_YEAR SV_YEAR
    ,PF_NAME PREFECTURE
    ,case p
        when 1 then '小学校'
        when 2 then '中学校'
        when 3 then '高校'
        when 4 then '短大'
        when 5 then '大学'
        when 6 then '大学院'
    end as KIND
    ,case p
        when 1 then ELEMENTARY
        when 2 then MIDDLE
        when 3 then HIGH
        when 4 then JUNIOR_CLG
        when 5 then COLLEGE
        when 6 then GRADUATE
    end as AMT
    ,p
from
    ENROLLMENT_STATUS
    natural join PREFECTURE
    cross join t
where 
    SURVEY_YEAR = '2020'
)
where
    p is not null
    and AMT is not null
group by 1,2,3
order by 2,p