这听起来就像你得到了你的总和，你只是除以4。你确实需要一个Coalesce（calulation，0）把null变成0。

Coalesce(SUM(DURATION_MINUTES) OVER (ORDER BY CY_WEEK ROWS BETWEEN 3 PRECEDING AND CURRENT ROW),0)/4

如果您需要一个移动平均值，则应使用AVG，而不是SUM：

SELECT CY_WEEK,
       RC,
       AVG(DURATION_MINUTES) OVER (ORDER BY CY_WEEK ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS rolling_avg
FROM MI_REPORT where CY_WEEK in ('2022_08','2022_09','2022_10','2022_11') and RC = 'FOO';

请记住，如果您将行限制为仅4周，并且有4周的窗口，则实际上并没有运行平均值，因为只有最后一行的平均值中包含整整4个期间。您可能需要删除 predicate ，并允许更长的时间段来查看真正的运行平均值。

SELECT CY_WEEK,
       RC,
       AVG(DURATION_MINUTES) OVER (ORDER BY CY_WEEK ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS rolling_avg
  FROM MI_REPORT where RC = 'FOO';

如果您只想查看特定四周的结果，请在外部查询块中应用该 predicate （* 在 * 计算运行平均值之后）：

SELECT CY_WEEK,
       RC,
       rolling_avg
 FROM (SELECT CY_WEEK,
              RC,
              AVG(DURATION_MINUTES) OVER (ORDER BY CY_WEEK ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) AS rolling_avg
         FROM MI_REPORT where RC = 'FOO')
where CY_WEEK in ('2022_08','2022_09','2022_10','2022_11')