Expression to find value for previous year SSRS - sql-server

Question

I need some help with expressions.I need a report that shows calcul of a field for current year as well as previous year respecting this rule expression(Last-Last Previous)/Last Previous*100. Also the report runs on a Year Parameter.
Below is an example for the result
for example i selected the years 2010 2011 2012
year
Data 2010 2011 2012
hp 14 25 30
Dell 17 18 20
and the result i want
year
Data 2010 2011 2012 2011/2012
hp 14 25 30 0.002 (Last -Last Previous)/(last Previous*100) =(30-25)/(25*100)
Dell 17 18 20 0.0040
How can i do this
SELECT
NON EMPTY
{[Measures].[Val]} ON COLUMNS
,NON EMPTY
{
[DimCAT].[lbl].[lbl].ALLMEMBERS * [DimDate].[Year].[Year].ALLMEMBERS
} ON ROWS
FROM [Data];

Answer 1

Via mdx you need to use a WITH clause.
The calculated member that is added is called 2011/12 but is actually the last member of the year hierarchy compared to the previous year - so maybe not exactly what you require:
WITH
MEMBER [DimDate].[Year].[2011/12] AS
(
Tail([DimDate].[Year].[Year].ALLMEMBERS).Item(0).Item(0)
-
Tail([DimDate].[Year].[Year].ALLMEMBERS).Item(0).Item(0).PrevMember
)
/
Tail([DimDate].[Year].[Year].ALLMEMBERS).Item(0).Item(0).PrevMember
* 100
SELECT
NON EMPTY
{
[DimDate].[Year].[Year].ALLMEMBERS
,[DimDate].[Year].[2011/12]
} ON COLUMNS
,NON EMPTY
{[DimCAT].[lbl].[lbl].ALLMEMBERS} ON ROWS
FROM [Data]
WHERE
[Measures].[Val];
Using the strToSet function you could get a single member set using the parameter:
WITH
SET [s] AS
StrToSet('{[DimDate].[Year].[Year].[' + #Yr + ']}')
MEMBER [DimDate].[Year].[LastVsPrev] AS
([s].Item(0).Item(0) - [s].Item(0).Item(0).PrevMember)
/
[s].Item(0).Item(0).PrevMember
* 100
SELECT
NON EMPTY
Union
(
{
[s].Item(0).Item(0).PrevMember.PrevMember : [s].Item(0).Item(0)
}
,{[DimDate].[Year].[LastVsPrev]}
) ON COLUMNS
,NON EMPTY
{[DimCAT].[lbl].[lbl].ALLMEMBERS} ON ROWS
FROM [Data]
WHERE
[Measures].[Val];

Answer 2

If you have the chance to change the source dataset i would bring the dataset with the year UNPIVOTed and with a Row_Number on Data with year descending order. That way you can filter the last two years you want.
(this was tested in SSRS 2008 there might be easier ways especially in later versions)
select
Data,[year],measure,ROW_NUMBER() over (partition by data order by [year] desc) i
from (values
('hp',2010,14),
('hp',2011,25),
('hp',2012,30),
('Dell',2010,17),
('Dell',2011,18),
('Dell',2012,20)) t (data,year,measure)
Data year measure i
hp 2010 14 3
hp 2011 25 2
hp 2012 30 1
Dell 2010 17 3
Dell 2011 18 2
Dell 2012 20 1
And do a Column Group on year and a row group on data.
Expression SUM(Field!Measure.Value) on the intersecting cell of the 2 groups.
Add Column after column group and add the Expression to the Header cell
=MAX(iif(Fields!i.Value = 2,Fields!year.Value.ToString(),""))+"/"+ MAX(iif(Fields!i.Value = 1,Fields!year.Value.ToString(),""))
and the next expression to the Cell
=iif(SUM(iif(Fields!i.Value = 2,Fields!measure.Value,0))=0,0,SUM(iif(Fields!i.Value = 1,Fields!measure.Value,0))-SUM(iif(Fields!i.Value = 2,Fields!measure.Value,0)) / (SUM(iif(Fields!i.Value = 2,Fields!measure.Value,0))*100))
I think the formula is OK, but it's returning different values than what you posted as expected.