Oracle 21c

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ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS';
ALTER SESSION SET NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF';
CREATE TABLE MI_REPORT (cy_week, rc, duration_minutes) AS
SELECT '2022_11', 'FOO', 97 FROM DUAL;
1 rows affected

WITH weeks (week) AS (
  SELECT '2022_05' FROM DUAL UNION ALL
  SELECT '2022_06' FROM DUAL UNION ALL
  SELECT '2022_07' FROM DUAL UNION ALL
  SELECT '2022_08' FROM DUAL UNION ALL
  SELECT '2022_09' FROM DUAL UNION ALL
  SELECT '2022_10' FROM DUAL UNION ALL
  SELECT '2022_11' FROM DUAL
),
averages (cy_week, rc, rolling_avg) AS (
  SELECT w.week,
         r.rc,
         AVG(COALESCE(r.duration_minutes, 0)) OVER (
           ORDER BY w.week ROWS BETWEEN 3 PRECEDING AND CURRENT ROW
         ) AS rolling_avg
  FROM   weeks w
         LEFT OUTER JOIN MI_REPORT r
         PARTITION BY (r.rc)
         ON (w.week = r.cy_week)
  WHERE  RC = 'FOO'
)
SELECT cy_week,
       rc,
       rolling_avg
FROM   averages
WHERE  cy_week in ('2022_08','2022_09','2022_10','2022_11');


CY_WEEK
RC
ROLLING_AVG


2022_08
FOO
0

2022_09
FOO
0

2022_10
FOO
0

2022_11
FOO
24.25