When creating a drill link, what must the last group by column be?

The last group by column in a drill link must be mapped. This requirement is crucial because a mapped column ensures that it has a direct association with another data element or dimension within the data model, allowing for accurate context when drilling down into the data. Mapping establishes a relationship between the original data and the drill-down information, enabling users to navigate seamlessly through related records or details.

Using a mapped column ensures that when users drill down, they do so in a meaningful way that retains the integrity and context of the data. The mapping allows the drill link to function correctly, providing users with relevant insights and maintaining the data structure necessary for effective analysis.

Since it is essential to have that relationship for operational efficiency and user experience, other types of columns, such as unmapped, summarized, or static, would not provide the necessary connectivity for a drill link to operate as intended. By requiring the last group by column to be mapped, the system can facilitate a clearer and more logical flow of information.