You have a worksheet based on the Part table.

To determine the total number of unique customers that have orders for each part, the COUNT function with a By qualifier is used. This counts the number of unique instances of a field within a set, which in this case is the Customer field within the IndependentDemands.

ReferencesThe COUNT function with a By qualifier is detailed in the Kinaxis RapidResponse documentation regarding aggregation functions, which specifies how to count unique occurrences of a field within a data set.