Order after rollup - oracle 11g
I'm not a ORACLE user but I've found an interesting article about it:

Oracle SQL GROUP BY – The Complete Guide

Scrolling down till the GROUPING Function you'll find and example on how use GROUP BY with ROLLUP:

Quoted from the article


  There are several SQL functions related to grouping that can help you
  identify and work with groups.
  
  Earlier in our examples, we noticed that subtotals had values of NULL
  for the columns that weren’t being considered in the group.
  
  How can we tell which values are subtotals and which values are NULL
  because of the underlying data?
  
  This is what the GROUPING function can help with.
  
  The GROUPING function takes a single column as a parameter. The output
  is either 1 or 0:
  
  It returns 1 if the column is being used as part of a subtotal and is
  showing NULL. It returns 0 if the underlying value is NULL or any
  other value.
  
  You can also order by these columns, to have the subtotals at the
  start or the end, instead of in the middle of the results.


According to this you could use the next syntax to produce the expected result:

SELECT
    Year,
    Month,
    SUM(Amount) as AmoutOfMone
FROM
    YourTable
GROUP BY ROLLUP (Year, Month)
ORDER BY
    GROUPING(Year) DESC,
    GROUPING(Month) DESC,
    Year ASC,
    Month ASC;


Due this question has a previous question here, I've used my fiddle to add this new information and it works properly.

/* aggregated sales by year-month */
SELECT
    T.CALENDAR_YEAR AS Year,
    T.CALENDAR_MONTH_DESC AS Month,
    SUM(S.AMOUNT_SOLD) AS AmountOfMoney
FROM
    SALES S
JOIN
    TIMES T
    ON T.TIME_ID = S.TIME_ID
WHERE S.PROD_ID = 1
GROUP BY ROLLUP (T.CALENDAR_YEAR, T.CALENDAR_MONTH_DESC)
ORDER BY GROUPING (T.CALENDAR_YEAR) DESC, 
         GROUPING (T.CALENDAR_MONTH_DESC) DESC, 
         CALENDAR_YEAR ASC,
         CALENDAR_MONTH_DESC ASC;



YEAR | MONTH | AMOUNTOFMONEY
---: | ----: | ------------:
null |  null |           450
2018 |  null |           450
2018 |     1 |           100
2018 |     2 |           200
2018 |     3 |           150


db&lt;>fiddle here