CREATE TABLE job_history (employee_id NUMBER, start_date TIME, end_date TIME, job_id CLOB, department_id NUMBER)
CREATE TABLE regions (region_id NUMBER, region_name CLOB)
CREATE TABLE locations (location_id NUMBER, street_address CLOB, postal_code CLOB, city CLOB, state_province CLOB, country_id CLOB)
CREATE TABLE departments (department_id NUMBER, department_name CLOB, manager_id NUMBER, location_id NUMBER)
CREATE TABLE countries (country_id CLOB, country_name CLOB, region_id NUMBER)
CREATE TABLE employees (employee_id NUMBER, first_name CLOB, last_name CLOB, email CLOB, phone_number CLOB, hire_date TIME, job_id CLOB, salary NUMBER, commission_pct NUMBER, manager_id NUMBER, department_id NUMBER)
CREATE TABLE jobs (job_id CLOB, job_title CLOB, min_salary NUMBER, max_salary NUMBER)

display all the information of employees whose salary is in the range of 8000 and 12000 and commission is not null or department number does not equal to 40.
SELECT * FROM employees WHERE salary BETWEEN 8000 AND 12000 AND commission_pct <> "null" OR department_id <> 40
SELECT * FROM "employees" WHERE ("commission_pct" <> "null" OR "department_id" <> 40) AND ("department_id" <> 40 OR "salary" <= 12000) AND ("department_id" <> 40 OR "salary" >= 8000)