You've learned how filter context and CALCULATE actually work. This is where it pays off. Part 3 of the DAX Fundamentals series covers the patterns you'll keep reaching for in real models, and why they behave the way they do.
We get into time intelligence (YTD, QTD, prior cycle, and why these functions return tables of dates rather than numbers), variables for cleaner and faster formulas, and SWITCH as the cure for nested IF chains nobody wants to maintain. Then inactive relationships and USERELATIONSHIP for when one fact table has two date columns fighting over the same date table.
The pattern that saves the most pain is calculation groups. Write three base measures, add one calc group with YTD, Prior Cycle, and YoY%, and you've replaced nine measures (and growing) with something you maintain in one place.
The video closes on the part most people skip: how the engine splits work between the Storage Engine and the Formula Engine, and why pushing work toward simple aggregations on a star schema is the difference between fast DAX and slow DAX.
