try this too....

;WITH mycte AS (

SELECT iCalendarDatCategoryID,vcCalendarCategoryCode,iSchoolYearCode,dtCalendarDay,

ROW_NUMBER() OVER(PARTITION BY iCalendarDatCategoryID ORDER BY dtCalendarDay) AS rn

FROM #Temp1

)

SELECT iSchoolYearCode, min(dtCalendarDay) as [Quarter Start Day], max(dtCalendarDay) as [Quarter Grade Closing] FROM mycte

group by iSchoolYearCode, rn

Order by min(dtCalendarDay)

it will also work 🙂