Query Top Ten Percent Department Salaries

Question

Find the employees whose salary is in the top 10% of their department.

Accepted Answer

```sql
SELECT id, name, department_id, salary
FROM (
    SELECT id, name, department_id, salary,
           PERCENT_RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) as rnk
    FROM employees
) t
WHERE rnk <= 0.1;
```

This query uses the `PERCENT_RANK()` window function to calculate the relative rank of each employee's salary within their respective department and filters for those in the top 10%.