CREATE TABLE [dbo].[voucherCr](
	[srno] [int] IDENTITY(1,1) NOT NULL,
	[vouchertype] [nvarchar](50) NULL,
	[voucherprefix] [nvarchar](50) NULL,
	[voucherno] [nvarchar](50) NULL,
	[crparty] [int] NULL,
	[cramount] [float] NULL)

CREATE TABLE [dbo].[voucherDr](
	[srno] [int] IDENTITY(1,1) NOT NULL,
	[vouchertype] [nvarchar](50) NULL,
	[voucherprefix] [nvarchar](50) NULL,
	[voucherno] [nvarchar](50) NULL,
	[drparty] [int] NULL,
	[dramount] [float] NULL)

CREATE TABLE [dbo].[voucher](
	[srno] [int] IDENTITY(1,1) NOT NULL,
	[vouchertype] [nvarchar](50) NULL,
	[voucherprefix] [nvarchar](50) NULL,
	[voucherno] [nvarchar](50) NULL,
	[dt] [date] NULL,
	[details] [nvarchar](255) NULL,
	[invoicetype] [nvarchar](50) NULL)

srno	vouchertype	voucherprefix	voucherno	dt	           details	invoicetype
1	PURCHASE	        P	                1	        2012-12-25		        RETAIL INVOICE
2	PAYMENT	        R	                1	        2012-12-25		
3	PURCHASE	        P	                2	        2012-12-25		        RETAIL INVOICE
4	PURCHASE	        P	                3	        2012-12-25		        RETAIL INVOICE

srno	vouchertype	voucherprefix	voucherno	crparty	cramount
1	PURCHASE	        P	                1	        2	        55000
2	PAYMENT	        R	                1	        1	        55000
3	PURCHASE	        P	                2	        2	         28000
4	PURCHASE	        P	                3	        2	        30550

srno	vouchertype	voucherprefix	voucherno	drparty	dramount
1	PURCHASE	        P	                 1	        4	        55000
2	PAYMENT	        R	                 1	        2	        55000
3	PURCHASE	        P	                 2	        4	        28000
4	PURCHASE	        P	                 3	        4	        29000
5	PURCHASE	        P	                 3	        97	        1160
6	PURCHASE	        P	                 3	        98	        290
7	PURCHASE	        P	                 3	        46	        50
8	PURCHASE	        P	                 3	        66	        50

SELECT Month(v.dt)      [Month],
       Sum(vc.cramount) Credit,
       Sum(vd.dramount) Debit
FROM   voucher v
       INNER JOIN voucherCr vc
               ON v.voucherno = vc.voucherno
                  AND v.voucherprefix = vc.voucherprefix
                  AND v.vouchertype = vc.vouchertype
       INNER JOIN voucherDr vd
               ON v.voucherno = vd.voucherno
                  AND v.voucherprefix = vd.voucherprefix
                  AND v.vouchertype = vd.vouchertype
GROUP  BY Month(v.dt) 

Month       Credit                 Debit
----------- ---------------------- ----------------------
12          290750                 168550

Select p.Month, SUM(p.cramount) As Credit, SUM(q.dramount) As Debit From 
	(
	 Select b.voucherno, DATENAME(MM, a.dt) As Month, SUM(b.cramount) As cramount From voucher As a 
	 JOIN voucherCr As b ON a.voucherno = b.voucherno AND a.vouchertype = b.vouchertype 
	 Group By b.voucherno, DATENAME(MM, a.dt) 
	) As p 
JOIN 
	(
		 Select b.voucherno, DATENAME(MM, a.dt) As Month, SUM(b.dramount) As dramount From voucher As a 
		 RIGHT JOIN voucherDr As b ON a.voucherno = b.voucherno AND a.vouchertype = b.vouchertype 
		 Group By b.voucherno, DATENAME(MM, a.dt) 
	) As q ON p.voucherno = q.voucherno 
Group By p.Month 

Select p.Month, SUM(p.cramount) As Credit, SUM(q.dramount) As Debit From 
	(
	 Select b.voucherno, DATENAME(YY, a.dt) As Year, DATENAME(MM, a.dt) As Month, SUM(b.cramount) As cramount From voucher As a 
	 JOIN voucherCr As b ON a.voucherno = b.voucherno AND a.vouchertype = b.vouchertype 
	 Group By b.voucherno, DATENAME(YY, a.dt), DATENAME(MM, a.dt) 
	) As p 
JOIN 
	(
		 Select b.voucherno, DATENAME(YY, a.dt) As Year, DATENAME(MM, a.dt) As Month, SUM(b.dramount) As dramount From voucher As a 
		 RIGHT JOIN voucherDr As b ON a.voucherno = b.voucherno AND a.vouchertype = b.vouchertype 
		 Group By b.voucherno, DATENAME(YY, a.dt), DATENAME(MM, a.dt) 
	) As q ON p.voucherno = q.voucherno 
Group By p.Month