Ceci est sans danger pour les années bissextiles et gère les plages de dates que les autres réponses ne gèrent pas actuellement.
DECLARE @d TABLE(from_date DATE, to_date DATE);
INSERT @d VALUES ('2013-11-25','2013-12-05');
;WITH n(n) AS
(
SELECT ROW_NUMBER() OVER (ORDER BY [object_id])-1 FROM sys.all_columns
),
d(n,f,t,md,bp,ep) AS
(
SELECT n.n, d.from_date, d.to_date,
DATEDIFF(MONTH, d.from_date, d.to_date),
DATEADD(MONTH, n.n, DATEADD(DAY, 1-DAY(from_date), from_date)),
DATEADD(DAY, -1, DATEADD(MONTH, 1, DATEADD(MONTH, n.n,
DATEADD(DAY, 1-DAY(from_date), from_date))))
FROM n INNER JOIN @d AS d
ON d.to_date >= DATEADD(MONTH, n.n-1, d.from_date)
)
SELECT original_from_date = f, original_to_date = t,
new_from_date = CASE n WHEN 0 THEN f ELSE bp END,
new_to_date = CASE n WHEN md THEN t ELSE ep END
FROM d WHERE md >= n
ORDER BY original_from_date, new_from_date;
Résultats :
original_from_date original_to_date new_from_date new_to_date
------------------ ---------------- ------------- -----------
2013-11-25 2013-12-05 2013-11-25 2013-11-30
2013-11-25 2013-12-05 2013-12-01 2013-12-05
Démo SQLFiddle avec des plages de dates plus longues et des années bissextiles
