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Explain how to implement cumulative sum in SQL.

SQLmedium0.3 min readPremium
Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Hexaware
Key Concepts Tested
partitionsparksqlwindow
Expert AnswerPremium
66 wordsInterview-ready
**Architectural Logic**: Window function with unbounded preceding for running total. **Implementation**: `SELECT date, amount, SUM(amount) OVER (ORDER BY date) AS cumulative_sum FROM sales`. Per group: `SUM(amount) OVER (PARTITION BY product_id ORDER BY date)`. **Frame**: Default ROWS UNBOUNDED PRECEDING. **Use**: Running balance; YTD. **Scalability**: Single pass; efficient. **Cost**: No extra scan. **Best Practice**: Deterministic ORDER BY (tie-breaker if needed); understand RANGE vs ROWS....
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