Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE employees (department_id VARCHAR, salary INTEGER, commission_pct VARCHAR)
### Question:
display the average salary of employees for each department who gets a commission percentage.
### Answer:
SELECT department_id, AVG(salary) FROM employees WHERE commission_pct <> "null" GROUP BY department_id