Is it possible to do a dynamic Rolling Avg in an expression? User can specify a parameter which will require the metric to show a dynamic Average Weekly Sales. A Time Dimension may or may not be present in the chart therefore, it must be intelligent enough to do
SUM(Sales for last n Periods)/n Periods
to yield that number
1. If a time period is not selected, then it would pick the most recent n Periods of sales,
2. else if selected, then use those n periods starting with the max date as the nth period,
3. else if time period is in the chart, then as per the definition of n prior periods
Not to mention there could be additional supporting dimensions of the Product Hierarchy, Customer Hierarchy etc.
