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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Introducing DAX Video CourseFree
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
Events in progress
The Events in Progress pattern has a broad field of application It is useful whenever dealing with events with a duration - events that have a start date and an end date The event is considered to be in progress… 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