Why the Optimiser does not run these STATS in parallel ? - response (3) by mjasrotia

Thanks Dieter, But could you please suggest any way to do this in a faster manner. I need to calculate these Ranks to calculate the Store Selling Metric which is non additive across the Product Hierarchy. COUNT(DISTINCT) is too expensive..
I have 6 of these RANK columns.
Is there a way I can create three tables with 2 Ranks each and update these Three tables in parallel. Will they complete in equal time ? Not sure but just asking for some advice
 
If any body else has tackled this problem in a better way
 
Thanks