-- パーティションの初めから現在の行まで --
SELECT a, SUM(b) OVER (PARTITION BY c ORDER BY d ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)
FROM T;
-- パーティションの3つ前から現在の行まで --
SELECT a, AVG(b) OVER (PARTITION BY c ORDER BY d ROWS BETWEEN 3 PRECEDING AND CURRENT ROW)
FROM T;
-- パーティションの3つ前から3つ先まで --
SELECT a, AVG(b) OVER (PARTITION BY c ORDER BY d ROWS BETWEEN 3 PRECEDING AND 3 FOLLOWING)
FROM T;
-- パーティションの現在の行からその先全てまで --
SELECT a, AVG(b) OVER (PARTITION BY c ORDER BY d ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING)
FROM T;