Window Functions in SQL: interview exercises

Window Functions in SQL: 6 test-checked interview exercises (Top N per group with ROW_NUMBER), each beside a worked example, with tests as you go. Free.

1. Top N per group with ROW_NUMBER
2. RANK versus DENSE_RANK
3. Running total per group
4. Compare with the previous row
5. Moving average with a frame
6. Share of the total

Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Progress is saved in your browser, and in your account if you sign in.

More SQL topics

• Select & Filter
• Aggregation
• Joins
• Subqueries & CTEs
• Strings, Dates & CASE
• Modifying Data
• Schema Design

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