🔥 Most Asked SQL Window Function Patterns (Real Business Problems)
If you master these patterns, you can solve many real-world SQL interview problems. 👇
🔹 Find Top 5 Products by Revenue in Each Category → ROW_NUMBER() / RANK() + PARTITION BY
🔹 Calculate Running Sales Revenue Over Time → SUM() OVER(ORDER BY Date)
🔹 Find Customer’s First Purchase Date → MIN() OVER(PARTITION BY Customer)
🔹 Find Latest Transaction of Every Customer → ROW_NUMBER() + PARTITION BY
🔹 Calculate Month-over-Month Sales Growth → LAG() + Date Functions
🔹 Compare Employee Salary With Department Average → AVG() OVER(PARTITION BY Department)
🔹 Find Highest Revenue Product in Each Category → RANK() + PARTITION BY
🔹 Calculate Customer Lifetime Value (Total Spend) → SUM() OVER(PARTITION BY Customer)
🔹 Identify Repeat Customers After First Purchase → ROW_NUMBER() + Filtering Logic
🔹 Calculate 7-Day Moving Average of Sales → AVG() OVER(ORDER BY Date ROWS BETWEEN)
🔹 Find Longest User Activity Streak → ROW_NUMBER() + Gaps & Islands
🔹 Calculate Product Contribution to Total Revenue → SUM() OVER() + Percentage Calculation
🔹 Detect Customers With Declining Purchases → LAG() + Comparison Logic
❤️ React if you want more SQL interview patterns based on real company problems!
5August 22, 2026 712 11
