The Sort By Column feature in Power BI causes side effects that are important to know when writing a DAX formula. This article explains these side effects and how to write correct DAX code to avoid getting incorrect results.  Read more

DAX has many time intelligence functions that are often redundant, offering different shorter syntaxes for longer more generic functions. However, sometimes the shorter syntax could be dangerous, as I explain in this blog post where I suggest using CALCULATE and…  Read more

This article describes how to use a measure to filter a Power BI visualization, and the different behaviors of a same filter between different visuals.  Read more

This article describes how to use the detail rows expression of a measure to obtain the equivalent of creating table functions in DAX. This allows the reusing of a table expression in multiple CALCULATE filters.  Read more

By answering to a student question I realized we often used a wrong calculation of customers age in DAX, and the simple solution is to borrow the same technique used in Excel, using INT and YEARFRAC rather than DATEDIFF or…  Read more

This article describes how to optimize DAX expressions with mutually exclusive calculations that might cause slow query performance.  Read more

This article describes a very common optimization pattern that relies on variables to optimize conditional expressions in DAX.  Read more

I received a question about how to implement the equivalent of a DISTINCTCOUNTX function in DAX. Well, such a function doesn’t exist in DAX, but imagine you want to write something like: The corresponding measure working in DAX is: In…  Read more

If you have a fiscal year starting in March, you can have a problem using the time intelligence functions in DAX. For example, by using February 28, the fiscal year starts on February 29th in leap years. By using February…  Read more

In SQL there are different types of JOIN, available for different purposes. This article shows the equivalent syntaxes supported in DAX and it was updated in May 2018.  Read more