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Level 1 — DAX Foundations+50 XP
Lesson 2
2. Measures vs Columns
Why measures conserve memory and dynamically adapt to visuals.
The Concept
Calculated columns are evaluated row-by-row during data refresh and consume RAM. Measures are calculated dynamically on demand in visual filter context.
Example DAX:
// Measure (Preferred for aggregations): Total Quantity = SUM(Sales[Quantity]) // Calculated Column (Consumes RAM per row): // Margin = Sales[Revenue] - Sales[Cost]
Rule of thumb in Power BI: If you want to aggregate numbers (totals, averages, ratios), always create a Measure, not a calculated column.
Try It Yourself
Create a measure called 'Total Quantity' that aggregates the Quantity column in the Sales table.
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