SSRS 2008 Dynamic Columns in a Matrix Report?

Question

I have SQL 2008 (not R2). I would like to have a matrix report where user can select one of the SQL resultset columns to be the matrix column group..

For example

A   B   Value
a1  b1  10
a2  b2  20
a3  b2  30

So the possible matrices could be (user selects from dropdown with A, B).

By A

       a1  a2  a3
Value  10  20  30

By B

       b1  b2
Value  10  50

Answer 1

i havne't actually done anything like this before, but i have a theory that you can modify the expression on the group to have an iif statement to change which field is grouped on

so, for the column group, change the expression for the gorup to something like =iif(ParameterValue=1,Field1,Field2)

Answer 2

This question should solve your problem. It is a way to use a parameter to refer to a field in your dataset.