lab4_ex9.sql

/*
SELECT department_id
FROM departments
MINUS
SELECT department_id
FROM employees
WHERE job_id = 'ST_CLERK';
*/

/*
SELECT country_id,country_name
FROM countries
MINUS
SELECT l.country_id,c.country_name
FROM locations l JOIN countries c
ON (l.country_id = c.country_id)
JOIN departments d
ON d.location_id=l.location_id;
*/

/*
SELECT employee_id, job_id, department_id
FROM EMPLOYEES
WHERE department_id=50
UNION ALL
SELECT employee_id, job_id, department_id
FROM EMPLOYEES
WHERE department_id=80;
*/

/*
SELECT EMPLOYEE_ID
FROM EMPLOYEES
WHERE JOB_ID='SA_REP'
INTERSECT
SELECT EMPLOYEE_ID
FROM EMPLOYEES
WHERE DEPARTMENT_ID=80;
*/

/*
SELECT last_name,department_id,TO_CHAR(null)dept_name
FROM employees
UNION
SELECT TO_CHAR(null),department_id,department_name
FROM departments;
*/