SELECT
	SUM(TotalDue) AS Total
  FROM 	
	(
	 SELECT
		YEAR(orderdate) AS YR,
		MONTH(orderdate) AS MO,
		TotalDue
	  FROM Sales.SalesOrderHeader
	) t1
 WHERE t1.yr = @year
   AND t1.mo < @month
 GROUP BY t1.yr, t1.mo

--Parameter
DECLARE @topMonth int=3;

--if a valid month is not selected, return all months 
IF @topMonth<=0 OR @topMonth>12 SET @topMonth=12

DECLARE @x varchar(2000), @x2 varchar(1000), @i int=1, 
		@p1 varchar(40)='SUM(case MONTH(orderdate) when ',
		@p2 varchar(50)='',
		@months varchar(300)='(';

IF OBJECT_ID('tempdb..##tmp') IS NOT NULL
	DROP TABLE ##tmp;

SET @x='SELECT YEAR(OrderDate) as orderyear, '+CHAR(13);

WHILE @i<=@topMonth
BEGIN
	SET @x=@x+@p1+CAST(@i AS varchar(2))+' then TotalDue end) as '
		+CAST(DATENAME(MONTH,(CAST(@i AS varchar(2))+'/1/2000')) AS varchar(20))
		+CASE WHEN @i<>@topMonth THEN ','+CHAR(13) ELSE CHAR(13) END

	SET @months=@months+CAST(DATENAME(MONTH,(CAST(@i AS varchar(2))+'/1/2000')) AS varchar(20))+
		CASE WHEN @i<>@topMonth THEN '+' ELSE ')' END

	SET @i=@i+1
END;

SELECT	@x=@x+'INTO ##tmp FROM Sales.SalesOrderHeader GROUP BY YEAR(OrderDate) ORDER BY orderyear',
		@x2 = 'SELECT *, '+@months+' AS GrandTotal FROM ##tmp ORDER BY orderyear'

EXEC(@x);
EXEC(@x2);

DROP TABLE ##tmp;