Under the Hood: How DAX Works with Filters

The content explains how DAX (Data Analysis Expressions) in Power BI processes filters, focusing on time intelligence functions. It demonstrates that functions like DATESYTD operate by generating a table of dates that is then applied as a filter, rather than directly filtering by a month or year column. By using DAX queries to deconstruct these functions, it shows how to manipulate the date context for calculations like year-to-date or same-period-last-year. This core understanding of DAX's table-based operations enables the creation of custom time intelligence logic for scenarios like moving averages or custom fiscal year calculations.