DAX Time Intelligence Functions
Time intelligence functions are an advanced feature of DAX. They are typically composite functions built on top of other more basic DAX features and have more stringent requirements for the structure of the underlying database. But since time related calculations are fundamental to almost all BI projects, early adopters of DAX started using the time intelligence functions almost immediately after the first release of DAX. Due to the advanced nature of these functions, questions naturally arise about how they work and why they work that way even when people managed to get the desired results.