Using ALLEXCEPT versus ALL and VALUES
This article describes the semantic difference between ALLEXCEPT and the joint use of ALL and VALUES, showing practical examples of the different results in Power BI and SSAS 2016.
If you are a loyal reader of this website, you probably already know that, in DAX, evaluation contexts are everything. We oftentimes teach to our students that once they understand evaluation contexts, DAX will hide no secret to them.
Yet, even with a solid understanding of evaluation contexts, it is still very easy to fall in some traps and, in this article, you will learn the subtle difference between using ALLEXCEPT or ALL and VALUES as filter parameters of CALCULATE.