DAX 101: Mark as Date table
Tabular models (including Power BI) require marking the Date table as a date table to get appropriate results with time intelligence calculations. This article explains why this setting is required.
We all mark the Date table as a date table, because we know it is a best practice. But why? What happens if you do not mark the Date table as such?
In order to understand the importance of marking the Date table, we can use a simple year-to-date calculation to refresh our understanding of DAX evaluation contexts: