Amazon·Software Engineer·Technical Phone Screen·Intermediate

Intermediate

Jun 2026

Summary

Amazon data engineer interview with a SQL-heavy question about ranking salaries within departments. Nothing too wild but it required more thought than I expected on the edge cases.

Questions Asked (1)

Write a SQL query to find the top 3 distinct salaries within each department and return all employees who earn those salaries.

Algorithms & Data StructuresData Modeling

Author's notes

I went straight for DENSE_RANK and partitioned by department, ordered by salary descending, then filtered where rank <= 3.

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AI HintsAI Generated

Suggested Approach

Use a window function like DENSE_RANK() to rank salaries within each department, then filter for ranks <= 3 and join back to the employee table to get all employees earning those salaries. This handles distinct salaries and ties correctly.

Pro tip: Clarify whether 'top 3 distinct salaries' means the three highest unique salary values (even if multiple employees share them) and whether to include ties; this shows attention to edge cases and business context.

1. Understand the requirements

Clarify what 'top 3 distinct salaries' means: the three highest unique salary amounts per department, and return all employees whose salary matches any of those amounts.

2. Rank salaries within each department

Use DENSE_RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) to assign a rank to each distinct salary, ensuring ties get the same rank.

3. Filter top 3 ranks

Select only rows where the dense rank is <= 3, which gives the top 3 distinct salaries per department.

4. Join back to employees

Join the filtered result back to the employee table on department_id and salary to retrieve all employees earning those top salaries.

5. Present the final query

Write the complete SQL query, ensuring correct syntax and handling of potential NULLs or duplicates.

Key Points to Mention

Use of DENSE_RANK() to handle distinct salaries and ties correctly.
Partitioning by department_id to rank within each department.
Filtering ranks <= 3 to get top 3 distinct salaries.
Joining back to the employee table to return all employees with those salaries.
Consideration of edge cases: departments with fewer than 3 distinct salaries, NULL salaries, and ties.
Alternative approaches like using a subquery with COUNT(DISTINCT salary) or ROW_NUMBER() with caveats.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.