aggregating data to getting running total - sql

Question

I have a query which outputs the below
I need to get it to provide a running total so for March it would give whats been paid in Feb and Mar, then for April Feb,Mar & Apr and so on.
Never come across needing this kind of aggregation before in SQL.

Answer 1

select
[monthid],
[month],
( select sum([paid]) from tbl t2 where t2.[monthid] <= t1.[monthid] ) as paid
from tbl t1

Answer 2

SELECT
T.MonthId
,T.[Month]
,T.Value
,RT.runningTotal
from Table_Name T
CROSS APPLY
(
SELECT SUM(value) as runningTotal
FROM Table_Name
WHERE MonthId <= T.MonthId
) as RT
order by T.MonthId
Test Data
declare #t1 TABLE (Monthid int, month varchar(10), Value decimal(18,2))
insert into #t1
values
(1,'JAN-13',35.00)
,(2, 'FEB-13',35.00)
,(3,'MAR-13',35.00)
,(4,'APR-13',35.00)
,(5,'JUN-13',35.00)
,(6,'Jul-13',35.00)
,(7,'Aug-13',35.00)
SELECT
T.MonthId
,T.[Month]
,T.Value
,RT.runningTotal
from #t1 T
CROSS APPLY
(
SELECT SUM(value) as runningTotal
FROM #t1
WHERE MonthId <= T.MonthId
) as RT
order by T.MonthId
RESULTS
MonthId Month Value runningTotal
1 JAN-13 35.00 35.00
2 FEB-13 35.00 70.00
3 MAR-13 35.00 105.00
4 APR-13 35.00 140.00
5 JUN-13 35.00 175.00
6 Jul-13 35.00 210.00
7 Aug-13 35.00 245.00

Answer 3

You can check this question and my answer on it. Turns out that recursive common table expression is the fastest method to get running total in SQL Server < 2012.
So in your case it could be something like:
with cte as
(
select T.MonthID, T.Month, T.Paid, T.Paid as Running_Paid
from Table1 as T
where T.MonthID = 118
union all
select T.MonthID, T.Month, T.Paid, T.Paid + C.Running_Paid as Running_Paid
from cte as C
inner join Table1 as T on T.MonthID = C.MonthID + 1
)
select *
from cte
option (maxrecursion 0)

Answer 4

Running totals in 2008 are kind of a pain. SQL Fiddle seems to have gone MIA again, but here's a simplistic example of how you can do it.
declare #t1 TABLE
(monthid int,
mth varchar(10),
paid decimal(18,2),
running_paid decimal(18,2))
insert into #t1
values (1,'JAN-13',35.00,0)
,(2, 'FEB-13',35.00,0)
,(3,'MAR-13',35.00,0)
declare #running decimal(18,2)
set #running= 0
update #t1 set running_paid = #running, #running= #running+ paid
select
*
from
#t1
Which will give you:
ID MTH PAID RUNNING_PAID
1 JAN-13 35.00 35.00
2 FEB-13 35.00 70.00
3 MAR-13 35.00 105.00
EDIT:
As Bogdan Sahlean points out, this is a very funky little process. You could also use a cursor:
declare #t1 TABLE
(monthid int,
mth varchar(10),
paid decimal(18,2)
)
insert into #t1
values (1,'JAN-13',35.00)
,(2, 'FEB-13',35.00)
,(3,'MAR-13',35.00)
declare #running table
(monthid int,
mth varchar(10),
paid decimal(18,2),
running_paid decimal(18,2))
declare c cursor
for select monthid,mth,paid from #t1
open c
declare #Id int
declare #Mth varchar(10)
declare #paid decimal(18,2)
declare #Running_Total decimal(18,2)
set #Running_Total = 0
fetch next from c
into #Id,#Mth,#paid
WHILE ##FETCH_STATUS = 0
begin
fetch next from c
into #Id,#Mth,#paid
select #Running_Total = #Running_Total + #paid --Here's this version's hack for running total
insert into #running values (#Id,#Mth,#paid,#Running_Total)
end
select
*
from
#running
They all kind of stink. This is a lot easier in SQL 2012.