London, England, GBSUMMARIZECOLUMNS best practices
Marco Russo & Alberto FerrariSUMMARIZECOLUMNS is a powerful and complex function in DAX that in 2025 can be used in measures. This article outlines the best practices when using this function to avoid incorrect results. Read more
Sideways recursion in DAX calculation groups
This article describes the sideways recursion triggered by invoking a calculation item from another calculation item, explaining why it should be avoided to steer clear of unexpected results. Read more
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SQLBI+ updates in August 2025
Marco RussoFor many years, SUMMARIZECOLUMNS has been a function dedicated to DAX queries and calculated tables, but it was not supported in DAX measures. Over time, Microsoft lifted the limitations, and in June 2024, the function was declared as fully supported… Read more
Understanding SUMMARIZECOLUMNS
This advanced paper explains how SUMMARIZECOLUMNS works internally, providing insight into how to control its behavior in queries and measures following a list of best practices. Read more
DAX Patterns
Time patterns
This post introduces the four time-related calculations patterns presented in this website The goal here is to help you choose the right pattern based on your specific needs Indeed when it comes to time-related calculations the choice of the pattern… More on DAX Patterns
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Optimizing DAX, Second Edition
Optimizing DAX is the state-of-the-art book on optimizing DAX expressions in Power BI and Analysis Services semantic models.
Learn how to locate performance bottlenecks, read the query plan and performance metrics, rewrite the slower part of an expression, and measure the performance improvements. Read more