ค่าเฉลี่ยเคลื่อนที่ของเหรียญรัสเซีย

WITH Russian_Medals AS (
  SELECT
    Year, COUNT(*) AS Medals
  FROM Summer_Medals
  WHERE
    Country = 'RUS'
    AND Medal = 'Gold'
    AND Year >= 1980
  GROUP BY Year)

SELECT
  Year, Medals,
  --- Calculate the 3-year moving average of medals earned
  ___ OVER
    (ORDER BY Year ASC
     ROWS BETWEEN
     ___ AND ___) AS Medals_MA
FROM Russian_Medals
ORDER BY Year ASC;