How to Display Last rolling 12 months in correct month order
I have an SSRS report that shows customer sales for the year and I have been asked to change it to the last 13 rolling months. I have changed my where clause to be:
WHERE (#First12Months.FirstSaleDate BETWEEN DATEADD(MM,-13,@ReportDate) AND (@ReportDate))
( @ReportDate is the last day of the month that needs to be displayed on the right of the matrix.)
This where clause pulls the correct data but it is still displaying in my monthsort order and I need to change this to the last 12 months so that the newest month is on the right and the oldest month is on the left. I cannot work out how to do the sort. My old sort is MonthSort which gives each month a number where April is 1 through to March = 12:
CASE WHEN Month(#First12Months.FirstSaleDate)<=3 THEN MONTH(#First12Months.FirstSaleDate)+9 ELSE MONTH(#First12Months.FirstSaleDate)-3 END AS MonthSort
but of course this is now incorrect as I need the month from @ReportDate to be number 13 and each month before that chronologically to be 1 number less.
I found this post which is the only one that seems to come close to what I need but unfortunately I simply don't understand what it is saying.
Dynamic table/output each month for report
How do I tell the MonthSort column which number to allocate to the months to get the correct sort order for a rolling 13 months?
As your data is in rows and your SSRS displays it in columns you can do the following: Add a sorting column to your sql query that uses an analytical function in order to give the (dense) rank of the month. That rank can then be used as a sorting criteria in SSRS.
Assuming your month column is called month, your query could look like this:
select t.*, dense_rank() over (order by month) rnk from t
That order could also be done descending like this:
select t.*, dense_rank() over (order by month desc) rnk from t
Let's have an example:
with t as (
select 2134 sales, cast('20190101' as date) month union all
select 3456 sales, cast('20190201' as date) month union all
select 234 sales, cast('20190301' as date) month union all
select 4567 sales, cast('20190401' as date) month union all
select 5678 sales, cast('20190501' as date) month union all
select 234 sales, cast('20190601' as date) month union all
select 756 sales, cast('20190701' as date) month union all
select 9 sales, cast('20190801' as date) month union all
select 24356134 sales, cast('20190901' as date) month union all
select 2456134 sales, cast('20191001' as date) month union all
select 234 sales, cast('20191101' as date) month union all
select 675 sales, cast('20191201' as date) month union all
select 86 sales, cast('20200101' as date) month union all
select 786 sales, cast('20200201' as date) month union all
select 715 sales, cast('20200301' as date) month union all
select 156 sales, cast('20200401' as date) month union all
select 123 sales, cast('20200501' as date) month union all
select 687 sales, cast('20200601' as date) month union all
select 45 sales, cast('20200701' as date) month
)
, t1 as (
select sales, month from t where t.month > dateadd(MONTH, -12, getdate())
)
select t1.*, DENSE_RANK() over (order by datefromparts(year(month), month([month]), 1)) rnk from t1
will return
