What is special or unique about the CALCULATE and CALCULATETABLE functions?
These are the only functions that allow you to modify the filter context of tables or measures.
* You can add to the existing filter context of the queries.
* You can override the filter context from the queries.
* You can remove the existing filter context from the queries.
Limitations :
* Filter parameters will only be able to work on one column at a time.
* Filter parameters will not be able to reference a metric.
