- COALESCE is used to replace NULL or missing values with a default value in SQL.
- In my project, Customer City sometimes had NULL, so we used COALESCE(City, ‘Unknown’).
- It ensures that mandatory fields always have a valid value.
- We also used COALESCE for numeric columns: COALESCE(Discount, 0) to avoid calculation errors.
- NULL handling prevents blank visuals or wrong aggregations in Power BI.
- It can be combined with CASE WHEN for complex conditional logic.
- Applied during extraction to reduce transformation effort later.
- Helps maintain data consistency and KPI accuracy.
- Avoids runtime errors in reports and calculations.
- So COALESCE ensures safe and clean handling of missing values.
What is COALESCE and NULL handling logic?
Updated on February 9, 2026
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