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Self-joins to compare employee salaries?

SQLmedium0.5 min readPremium
Frequency
Low
Asked at 1 company
Category
487
questions in SQL
Difficulty Split
130E|271M|86H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
Snowflake
Key Concepts Tested
join
Expert AnswerPremium
90 wordsInterview-ready
Self-join for salary comparison: SELECT e1.name, e1.salary, e2.name AS higher_sal_name, e2.salary FROM emp e1 JOIN emp e2 ON e1.salary < e2.salary. To find employees with no one earning more in same dept: SELECT * FROM emp e1 WHERE NOT EXISTS (SELECT 1 FROM emp e2 WHERE e2.dept = e1.dept AND e2.salary > e1.salary). Or use MAX with GROUP BY. **Why it matters**: Design choices compound at scale—wrong approach can cause 100× overhead....
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