Você pode usar
Recursive CTE . Não consigo pensar em nenhuma maneira melhor. ;WITH cte
AS (SELECT *,
Row_number()OVER(ORDER BY start) rn
FROM Yourtable),
rec_cte
AS (SELECT *,
( [End] - Start ) AS st,
1 AS grp
FROM cte
WHERE rn = 1
UNION ALL
SELECT a.*,
CASE
WHEN st + ( a.[End] - a.Start ) >= 500 THEN a.[End] - a.Start
ELSE st + ( a.[End] - a.Start )
END,
CASE
WHEN st + ( a.[End] - a.Start ) >= 500 THEN b.grp + 1
ELSE grp
END
FROM cte a
JOIN rec_cte b
ON a.rn = b.rn + 1)
SELECT Min(Start) as Start,
Max([End]) as [End],
Max(st) as Quantity
FROM rec_cte
GROUP BY grp
OPTION (maxrecursion 0)
