Find First and Last Employee Salaries

Question

Find the first and last employee salary in each department using window functions.

Accepted Answer

```sql
SELECT DISTINCT 
    department_id,
    FIRST_VALUE(salary) OVER (PARTITION BY department_id ORDER BY salary ASC) AS first_salary,
    LAST_VALUE(salary) OVER (PARTITION BY department_id ORDER BY salary ASC RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS last_salary
FROM employees;
```

This query uses the `FIRST_VALUE` and `LAST_VALUE` window functions partitioned by `department_id` to identify the minimum and maximum salary values within each department.