Dimension metrics
The majority of DAX measures apply aggregating functions to numeric columns of fact tables. However, several of the most important metrics of a dataset are those that focus on dimension tables, such as the count of customers who’ve purchased and those who haven’t.
It can also be necessary to count the distinct values of a dimension column such as the number of postal codes sold to or the number of distinct marketing promotions over a period of time.
In the dataset for this project, the customer dimension table is exclusive to the Internet Sales fact table, and the measure should only count customers with internet sales history.
Additionally, slowly changing dimension logic has been implemented so that a single customer defined by the CustomerAlternateKey column could have multiple rows defined by the CustomerKey column.
The following two DAX measures count the number of unique customers and products with internet sales history:
...