how can i subtract the data from sql table - sql-server

Question

How can i subtract two columns based on AccountGroupId 4 - AccountGroupId 5
I have data like :
ID Month Year AccountGroupName AccountGroupId Balance
1 February 2014 Expense 5 200
2 February 2014 Income 4 300
3 March 2014 Expense 5 250
4 March 2014 Income 4 200
Desired Result :
ID Month Year AccountGroupName AccountGroupId Balance
1 February 2014 Income 4 100
2 March 2014 Expense 5 -50
Query :
IF OBJECT_ID('tempdb..#temptbale') IS NOT NULL DROP TABLE #temptbale
IF OBJECT_ID('tempdb..#subTable') IS NOT NULL DROP TABLE #subTable
SELECT
(DATENAME(Month,JD.CreatedDateTime)) as [Month],
DATEPART(yyyy ,JD.CreatedDateTime) as [Year],
AG.AccountGroupName,
AT.AccountGroupID,
Sum(A.OpeningBalance) as Balance
into #temptbale
FROM AccountGroup AG
INNER JOIN AccountType AT ON AG.AccountGroupID=AT.AccountGroupID
Right join Account A on A.AccountTypeID = AT.AccountTypeID
Inner join JournalMasterDetail JD on JD.AccountID = A.AccountID
where AG.AccountGroupID > 3 and year(JD.CreatedDateTime) = year(getdate())
and datepart(dy, JD.CreatedDateTime) <= datepart(dy, getdate())
group by
A.AccountName,
JD.CreatedDateTime,
AG.AccountGroupName,
A.OpeningBalance,
AT.AccountGroupID
select ROW_NUMBER() OVER(ORDER BY [Month]) AS 'ID',[Month],[Year],AccountGroupName,AccountGroupID,SUM(Balance)as Balance
into #subTable
from #temptbale
group by
[Month],
AccountGroupName,
AccountGroupID,
[Year]
order by
[Month]
select * from #subTable

Answer 1

You can run this query
select t.Month,t.Year
,Case when tblExp.Balance > tblIncome.Balance then tblExp.AccountGroupName else tblIncome.AccountGroupName end as AccountGroupName
,Case when tblExp.Balance > tblIncome.Balance then tblExp. AccountGroupId else tblIncome. AccountGroupId end as AccountGroupId
,tblIncome.Balance - tblExp.Balance as Balance
from table t
inner join(select * from table where AccountGroupId = 4) as tblExp on tblExp.year = t.year and tblexp.Month = t.Month
inner join(select * from table where AccountGroupId = 5) as tblIncome on tblIncome.year = t.year and tblIncome.Month = t.Month
group by t.Month,t.Year
It's joining the Month and year with two derived tables as Income and expense