Using KEEPFILTERS in DAX
This article explains how to use KEEPFILTERS to intersect instead of overriding an existing filter context in DAX, simplifying the code and improving performance.
There is an additional disclaimer to this article – if you think that it is too complex, just skip to the next paragraph, but if you think you already know KEEPFILTERS, please read this. If you read our book The Definitive Guide to DAX, you might consider KEEPFILTERS as only necessary when you have arbitrarily shaped filters that you do not want to lose by applying additional filters on individual columns. However, KEEPFILTERS’ relevance is quite a bit wider. In a way, this article is a way of making up for not having included a better description of KEEPFILTERS in our book.