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Explain Coalesce vs ISNULL. What are the differences in SQL?

SQLeasy0.4 min readPremium
Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
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1,863
across 7 categories
Asked at these companies
Fractal
Key Concepts Tested
sql
Expert AnswerPremium
83 wordsInterview-ready
**Architectural Logic**: COALESCE is standard; ISNULL is SQL Server-specific—portability and flexibility differ. **COALESCE**: Standard SQL; returns first non-NULL from list; `COALESCE(a, b, c)`. **ISNULL**: SQL Server; two args only; `ISNULL(a, b)`. **Equivalence**: For two args, same result. **Differences**: COALESCE portable; handles multiple fallbacks. ISNULL: type of first arg; COALESCE can change type. **Example**: `COALESCE(phone, email, 'N/A')` vs `ISNULL(phone, 'N/A')`....
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