[오라클로 배우는 데이터베이스 개론과 실습] 실무 실습 A.7 집합연산자 사용

A.7 집합 연산자 사용

 

샘플 문제

SELECT EMPLOYEE_ID, JOB_ID
FROM EMPLOYEES
UNION
SELECT EMPLOYEE_ID, JOB_ID
FROM JOB_HISTORY

 

문제 1

SELECT EMPLOYEE_ID, JOB_ID, DEPARTMENT_ID
FROM EMPLOYEES
UNION ALL
SELECT EMPLOYEE_ID, JOB_ID, DEPARTMENT_ID
FROM JOB_HISTORY
ORDER BY EMPLOYEE_ID ASC;

 

문제 2

SELECT EMPLOYEE_ID, JOB_ID
FROM EMPLOYEES
INTERSECT
SELECT EMPLOYEE_ID, JOB_ID
FROM JOB_HISTORY;

 

문제 2 - 계속

 

???

 

문제 3

SELECT EMPLOYEE_ID
FROM EMPLOYEEs
MINUS
SELECT EMPLOYEE_ID
FROM JOB_HISTORY;