Simplify your DAX in Power BI with window functions

09:00 - 10:30 Neon (80) Back to event schedule

Window functions are a relatively new addition to DAX. They aim to simplify certain data operations that are very intuitive in tools like Excel, but weren't so easy to replicate in DAX so far. In this session I'll introduce you to the 3 main window functions: INDEX, OFFSET and WINDOW. Even though their syntax may seem a bit complex at first glance, I'll show you that using them is not a rocket science. You will learn a number of real-life use-cases and code patterns that you can start using in your own Power BI reports from the very next day. Based on these use-cases, you will see the potential of window functions to not only simplify a previously lengthy DAX code but also optimize it in terms of performance. I will also introduce you to some 'false friends' of window functions - cases where it might actually not be the best idea to use them. Selected use cases which you will learn include: time intelligence, running totals, cumulative calculations, Pareto charts and Excel-style calculations (e.g. delta compared to last item). During this session you will: - understand the concept and syntax of window functions in DAX. - learn when to use window functions and when not to. - discover a number of use-cases for window functions that you can immediately start using in your own work. It would be great if prior to attending this session you have a general understanding of DAX and its key concepts.


Greg Strzyminski

Power BI Consultant & Trainer, Senior BI Developer at Kearney

Grzegorz (feel free to call him Greg) is a Senior BI Developer at Kearney Warsaw. He serves as a Power BI technical Team Lead for the Business Intelligence team in Poland. He has proved his lecturing and teaching skills by running Power BI community events as well as internal trainings at Kearney at all levels, ranging in audience size from 5 to 250. Greg has been leading a number of Power BI workshops aimed at experienced professionals, students as well people willing to explore the art of possible in Business Intelligence. He has experience at conveying his knowledge at various levels, ranging from beginner to expert. Greg holds a number of Microsoft Certifications including Power BI - related ones: PL-300, DA-100 and 70-778.