Предполагается, что у вас есть таблица с датами (dimDate ниже):
DECLARE @fromDate DATE= '2019-05-04', @ToDate DATE= '2019-06-01', @NbrOfWeeks INT
SELECT @NbrOfWeeks = DATEDIFF(day, @fromdate, @todate) / 7
SELECT WeekNbr,
MIN(DateCode) as StartDate,
MAX(DateCode) as EndDate
FROM
(
SELECT NTILE(@NbrOfWeeks) OVER(
ORDER BY DateCode ASC) AS WeekNbr,
DateCode
FROM dimDate
WHERE DateCode BETWEEN @fromDate AND @ToDate
) m
GROUP BY WeekNbr;