with T as
(
    select
        substr(sales_date, 0, 8) 'YEAR_MONTH'
        ,sum(sales_amt) 'MONTH_AMT'
    from
        SALES
    where
        updated_no is null
        and sales_date >= '2023-01-01'
    group by
        substr(sales_date, 0, 8)
),
Y as
(
    select
        X.YEAR_MONTH
        ,sum(X.MONTH_AMT) over (order by X.YEAR_MONTH rows 11 preceding) YEAR_MOVE_AMT
    from
    (
        select
            substr(sales_date, 0, 8) 'YEAR_MONTH'
            ,sum(sales_amt) 'MONTH_AMT'
        from
            SALES
        where
            updated_no is null
        group by
            substr(sales_date, 0, 8)
    ) X
)
select
    T1.YEAR_MONTH
    ,T1.MONTH_AMT
    ,sum(T2.MONTH_AMT) 'CUML_AMT'
    ,Y.YEAR_MOVE_AMT
from
    T T1
    inner join T T2 on T1.YEAR_MONTH >= T2.YEAR_MONTH
    left join Y on T1.YEAR_MONTH = Y.YEAR_MONTH
group by
    T1.YEAR_MONTH
    ,T1.MONTH_AMT