Complicated ledger query

query.sql

-- Count the number of months where the 12 month moving average of after-tax expenses excluding travel (basically, normal ordinary expenses) went up, down, or didn't change

select
    sum(case when pct_change > 0 then 1 else 0 end) as up,
    sum(case when pct_change < 0 then 1 else 0 end) as down,
    sum(case when pct_change = 0 then 1 else 0 end) as no_change
from (
    select
        xtn_month,
        ((expenses - prev) / prev) * 100 as pct_change
    from (
        select
            xtn_month,
            expenses,
            lag(expenses, 1) over (rows unbounded preceding) as prev
        from (
            select
                xtn_month,
                avg(amount) over (rows 12 preceding) as expenses
            from (
                select
                    xtn_month,
                    sum(amount) as amount
                from
                    ledger
                where
                    account ~ 'Expenses'
                    and account !~ 'Depreciation'
                    and account !~ 'Taxes'
                    and account !~ 'Interest'
                    and account !~ 'Insurance'
                    and account !~ 'Travel'
                    and not virtual
                group by
                    xtn_month
            ) x
            order by
                xtn_month
        ) x
    ) x
) x;