Building complex measures with DAX
Power BI uses a programming language called DAX for creating calculated columns, calculated tables, and measures. This language can be used to easily create complex expressions to implement business rules.
As we discussed in the previous chapter, measures are calculations that define business rules. It is not a business rule if we cannot define it mathematically. We don't say "We need most of our customers to like us"; we say "We need a 90% or better score on all customer surveys returned." We don't say "We need to create reports for people to use"; we say "This report should be used at least once a week by 73.4% of managers in finance."
DAX uses a Microsoft Excel-like language for these calculations. That means if you have ever created a formula in Excel, you are already well on your way to learning DAX! If you haven't, know that millions, if not billions, of people around the world use...
