Find the second highest salary.
Asked in the Virtual Interview stage, SQL assessment section. Treat duplicate salary values as one salary level. If fewer than two distinct non-NULL salaries exist, return a single row with a NULL result.
second_highest_salary.| Column | Type | Description |
|---|---|---|
| employee_idPK | INT | Unique employee identifier |
| employee_name | VARCHAR(100) | Employee name |
| department | VARCHAR(80) | Employee department |
| salary | NUMERIC(12,2) | Annual employee salary |