Khotso, In MDX you would have to use
Khotso,
In MDX you would have to use ParallelPeriod function. Example of MDX query is here:
http://www.ssas-info.com/analysis-services-faq/27-mdx/55-mdx-query-to-get-latest-months-and-previous-years-same-months-data-parallelperiod