SQL Quest › SQL Interview Questions › Aggregation & Grouping
Average Salary by Department
Comp planning wants a single-line summary per department: department name and average salary (rounded to the nearest dollar so the spreadsheet doesn't show 12 decimals).
Show department and ROUND(AVG(salary), 0) AS avg_salary. Group by department. Order by avg_salary descending.
The pattern is GROUP BY → one aggregate per metric → ROUND for presentation. AVG() ignores NULLs by default, so missing salaries don't poison the mean (though they do shrink the denominator).
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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: Engineering | 85000, Marketing | 60000
Hint
SELECT, GROUP BY, AVG, and open the hint there if you stall.Concepts
SELECT GROUP BY AVG ROUND Aggregation
Practise the topic: SQL practice questions · GROUP BY exercises
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