SUMX : An "iterator" function that performs a calculation row-by-row before summing the results.
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DATEADD : Used for time intelligence, such as calculating "Year-Over-Year" growth by shifting dates. SUMX : An "iterator" function that performs a
RANKX : Automatically ranks items (like products or sales reps) based on a specific value. Practical PowerPivot & DAX Formulas for Excel 2010 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: