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Identify who is a manager and who is not.

General/Othereasy0.4 min readPremium

Manager = employee who is parent_id for at least one other. SQL: SELECT e.id, e.name, CASE WHEN EXISTS (SELECT 1 FROM employees e2 WHERE e2.manager_id = e.id) THEN 'Manager' ELSE 'Non-Manager' END AS role FROM employees e. WHY: EXISTS is efficient—short-circuits; avoids...

🤖 Analyze Your Answer
Frequency
Low
Asked at 1 company
Category
243
questions in General/Other
Difficulty Split
151E|43M|49H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
HashedIn
Key Concepts Tested
sql

Why This Question Matters

This easy-level General/Other question appears frequently in data engineering interviews at companies like HashedIn. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (sql) will help you answer variations of this question confidently.

How to Approach This

Start by clearly defining the core concept being asked about. Interviewers want to see that you understand the fundamentals before diving into implementation details. Structure your answer with a definition, then explain the practical application with a concise example.

Expert Answer
79 words

Manager = employee who is parent_id for at least one other. SQL: SELECT e.id, e.name, CASE WHEN EXISTS (SELECT 1 FROM employees e2 WHERE e2.manager_id = e.id) THEN 'Manager' ELSE 'Non-Manager' END AS role FROM employees e. WHY: EXISTS is efficient—short-circuits; avoids duplicate scans. Handle NULL manager_id (CEO). SCALABILITY: Index on manager_id; for large orgs, consider materialized view or closure table for hierarchy queries. COST: EXISTS subquery is typically index-only; IN (subquery) can be less optimal in some optimizers.

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According to DataEngPrep.tech, this is one of the most frequently asked General/Other interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.

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