SLICER to choose column

Hi, 

I would like to create slicer where user can choose column.

e.g. I have the columns: number of IT user, number of clients and so on.

The user can choose in slicer column "number od IT user" and in dashboard he get data from this column.

I tried to use case e.g CASE  when "number of IT user" then number of IT user.

Unfortunately it doesn't work.

Have you got any idea?:)