I remember IBM had produced a pdf a few years ago for Cognos 8 Report Studio with examples of MDX functions when building reports using cubes.
I can't find that pdf anywhere now.
Does anyone know where I can find it? I checked IBM's web site but came up empty.
All the MDX functions are available in Report Studio. If you go to the toolbox, you will see a folder called 'Dimensional Functions; from 10.1 onwards.
There is a PDF which explains how to write efficient OLAP queries with examples of what happens when you use relational vs dimensoinal functions. It has the examples to explain the point. Attached.
The original PDF is still available in the Cognos proven practices area at
http://www.ibm.com/developerworks/views/analytics/libraryview.jsp?sort_by=Title&sort_order=1&show_abstract=true&show_all=false&search_flag=true&product_by=Cognos&topic_by=All%20Topics&type_by=All%20Types&search_by=cognosppreportingdimensionalqueries&Submit.x=0&Submit.y=0
If you download the PDF which lists all the mdx functions and gives examples of each use make sure you also grab the zip file which can be used against the Cognos sample data.