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Self-Join: Manager Salary Comparison
Compare each employee's salary to their manager's salary. Show emp_name, emp_salary, manager_name, manager_salary, and pct_of_manager (employee salary as a percentage of manager salary, rounded to 1 decimal). Include employees with no manager (show NULL for manager fields). Sort by pct_of_manager descending (NULLs last). Self-joins on manager_id are asked at every FAANG company because hierarchical data is everywhere.
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Schema
employees
| emp_id | name | department | position | salary | hire_date | manager_id | performance_rating |
|---|---|---|---|---|---|---|---|
| 1 | Alice Johnson | Engineering | Senior Developer | 95000 | 2019-03-15 | 5 | 4.5 |
| 2 | Bob Smith | Engineering | Developer | 75000 | 2020-06-01 | 1 | 3.8 |
| 3 | Carol Williams | Marketing | Marketing Manager | 85000 | 2018-09-20 | NULL | 4.2 |
Expected output: pct_of_manager = 70.0
Hint
Concepts
SELECT Self-Join LEFT JOIN CASE ROUND
Practise the topic: SQL practice questions · JOIN practice · CASE WHEN practice · Advanced SQL interview questions
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