Summary

The ability to ingest and access data is crucial to every BI project. In Power BI, this data ingest and access is driven by a powerful functional language and query engine, M. The Power Query M language provides a robust, scalable, and flexible engine for data retrieval, cleansing, and transformation.

In this chapter, we dove into Power BI Desktop’s data transformation experience and walked through the process of establishing and managing data source connections and queries. We explored both import and DirectQuery storage modes, as well as creating reuseable queries within the Power BI Service called dataflows. We then demonstrated powerful data transformation techniques, including filtering and cleansing data, creating custom columns, and combining and merging multiple queries. Finally, we demonstrated how to profile data, diagnose non-performant queries, and how to extend the core M library of functions.

In the next chapter, we leverage the knowledge gleaned...