Imagine u have this:
load * Inline [
If(Nb = Previous(Nb),
If(Date = Previous(Date),1)) as Flag
Order By Nb, Date;
Drop Table t0;
If you want to do it on dashboard, try creating a table with:
+ Dimension: Article Number, Date
+ Measure: Count( Article Number) for times of purchasing.
If times of purchasing is larger than 1, that row data is duplicated.
If you want to mark it as a flag, you have to do it in Script load with group by and join function.