DATEADD : Used for time intelligence, such as calculating "Year-Over-Year" growth by shifting dates.
SUMX : An "iterator" function that performs a calculation row-by-row before summing the results.
: Practical examples show how to compare current performance against the past and handle tricky calculations like running totals or non-numeric values. Practical PowerPivot & DAX Formulas for Excel
If you're looking for the "power" in PowerPivot, these common DAX functions highlighted by expert resources like Microsoft Support and Analytics Vidhya are essential:
RANKX : Automatically ranks items (like products or sales reps) based on a specific value. Practical PowerPivot & DAX Formulas for Excel 2010 DATEADD : Used for time intelligence, such as
CALCULATE : The most powerful function, used to modify the filter context of a calculation.
In his book author Art Tennick provides a comprehensive guide for extracting actionable insights from massive corporate datasets. This "hands-on" resource is particularly noted for: If you're looking for the "power" in PowerPivot,
: It contains over 250 downloadable DAX formulas that cover everything from basic filtering to complex statistical and time-intelligence functions.