Spotfire Over Function

You can use Over function in spotfire
Over means grouping in spotfire
You can use in
1) Calculated columns

• Sum(Amount) : It give total sum in datatable
• Sum(Amount) over region: It gives sum for each region so basically group by region        

2) In graph custom expression
        In graph if sum(amount) in in Y axis and in x axis is region then chart automatically gives group by for each x axis values(here region)
So over function gives best results with when x axis is having date field with hierarchy for year>>month etc.

• Avg(Amount) Over All([Axis.X]) : It gives Total average for all nodes of x axis. So basically it draws a single avg line

• Avg(Amount) Over Parent([Axis.X]) : It gives avg line for parent node of x axis. Say x asis is year>> month then this will be avg line for Year.

• Avg(Amount) over AllPrevious(Axix.X) :  It gives cumulative sum

• Avg(Amount)  over Lastperiods(3,Axis.X) : Moving average for last 3 month
• Sum(Amount) - Sum(Amount) over previous([Axis.X] : Seeing how the current amount is doing over last month.