sql server calculate cumulative number per month for different year - sql

Question

I have a table with "date" column. Each row represents a survey.
date
11/19/2013 5:51:41 PM
11/22/2013 1:30:38 PM
11/23/2013 3:09:17 PM
12/2/2014 5:24:17 PM
12/25/2014 11:42:56 AM
1/6/2014 2:24:49 PM
I want to count the number of survey per month cumulatively. As you see from the above table, there are 3 surveys for Nov 2013, 2 surveys for Dec 2013, 1 survey for Jan 2014. The cumulative number of survey per month would be:
month | year | number_of_survey
11 | 2013 | 3
12 | 2013 | 5
1 | 2014 | 6
I have this query which shows correct number of surveys for 2013, and number of survey for 2014 is not cumulative.
with SurveyPerMonth as -- no of Survey per month
(
select datepart(month, s.date) as month,
datepart(year, s.date) as year,
count(*) as no_of_surveys
from myTable s
group by datepart(year, s.date), datepart(month, s.date)
)
select p1.month, p1.year, sum(p2.no_of_surveys) as surveys -- cumulatively
from SurveyPerMonth p1
inner join SurveyPerMonth p2 on p1.month >= p2.month and p1.year>=p2.year **-- the problem is probably comes from this line of code**
group by p1.month, p1.year
order by p1.year, p1.month;
This query returns:
month | year | surveys
11 | 2013 | 3
12 | 2013 | 5
1 | 2014 | 1 // 2014 is not cumulative
How can I calculate cumulative number of surveys per month for 2014 as well?

Answer 1

Something like this ?
SELECT date = create_date INTO #myTable FROM master.sys.objects
;WITH perMonth ( [year], [month], [no_of_surveys])
AS (SELECT DatePart(year, s.date) ,
DatePart(month, s.date),
COUNT(*)
FROM #myTable s
GROUP BY datepart(year, s.date),
datepart(month, s.date))
SELECT [year],
[month],
[no_of_surveys] = ( SELECT SUM([no_of_surveys])
FROM perMonth agg
WHERE (agg.[year] < pm.[year])
OR (agg.[year] = pm.[year] AND agg.[month] <= pm.[month]))
FROM perMonth pm
ORDER BY [year], [month]
Edit: seems I missed the ball with < and >, fixed it and added small example

Answer 2

'--This should work.I have added a new column 'monthyear'
with surveypermonth as -- no of survey per month
(
select datepart(month, s.date) as month,
datepart(year, s.date) as year,
datepart(year, s.date) *100 + datepart(month, s.date) as monthyear,
count(*) as no_of_surveys
from test s
group by datepart(year, s.date), datepart(month, s.date),datepart(year, s.date)*100 + datepart(month, s.date)
)
select a.month,substring(cast(monthyear as varchar(6)),1,4) as year,surveys from
(
select p1.month, p1.monthyear as monthyear, sum(p2.no_of_surveys) as surveys
from surveypermonth p1
inner join surveypermonth p2 on p1.monthyear>=p2.monthyear
group by p1.month, p1.monthyear
--order by p1.monthyear, p1.month
)a