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Microsoft·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Microsoft SQL interview, got a classic ranking problem. Short and to the point, nothing too wild.

Questions Asked (1)

Q1

Write a SQL query to rank employees by salary within each department.

Algorithms & Data StructuresData Modeling
Author's notes

Pretty standard window function territory.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: ranking method (e.g., ROW_NUMBER, RANK, DENSE_RANK) and handling ties. Then write a SQL query using a window function partitioned by department and ordered by salary descending. Finally, explain the differences between ranking functions and when to use each.

Pro tip: Demonstrate awareness of performance implications: window functions can be expensive on large datasets, so consider indexing on (department_id, salary) to optimize. Also, mention that the choice of ranking function depends on business rules for ties.

1. Clarify requirements

Ask whether ties should receive the same rank or sequential numbers, and whether to include all employees or only top N per department.

2. Choose ranking function

Select ROW_NUMBER, RANK, or DENSE_RANK based on tie-handling: ROW_NUMBER gives unique sequential numbers, RANK leaves gaps after ties, DENSE_RANK does not leave gaps.

3. Write the query

Use a window function with PARTITION BY department_id ORDER BY salary DESC. Example: SELECT employee_id, department_id, salary, RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) AS salary_rank FROM employees;

4. Explain and validate

Walk through the query logic, discuss edge cases (e.g., null salaries, multiple employees with same salary), and suggest how to test with sample data.

Key Points to Mention

  • Window functions: ROW_NUMBER, RANK, DENSE_RANK and their differences
  • PARTITION BY and ORDER BY clauses in window functions
  • Handling ties in salary: business implications of each ranking method
  • Performance considerations: indexing on (department_id, salary)
  • Alternative approaches: correlated subqueries or self-joins (and why window functions are better)
  • Portability across SQL dialects (e.g., MySQL 8+, PostgreSQL, SQL Server)

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