[Oracle] 오라클 - 집합 연산자

[Oracle]
오라클 - 집합 연산자

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✔️  - UNION : 합집합, 교집합은 한번만 출력된다. 

개발부거나 인천에 해당되는 직원이 출력된다. (둘 다 해당되어도 1번만 나옴)

	SELECT name, city, dept FROM emp WHERE dept = '개발부' 
	UNION
	SELECT name, city, dept FROM emp WHERE city = '인천' ;

 

 

✔️ - UNION ALL : 중복 데이터도 출력  (개발부이면서 인천인 애들이 1번 더 나옴)

	SELECT name, city, dept FROM emp WHERE dept = '개발부' 
	UNION ALL
	SELECT name, city, dept FROM emp WHERE city = '인천' 
	ORDER BY city;

 

 

✔️ - MINUS : 차집합 (개발부에서 인천 빼버리기)

	SELECT name, city, dept FROM emp WHERE dept = '개발부' 
	MINUS
	SELECT name, city, dept FROM emp WHERE city = '인천'

 

 

✔️ - INTERSECT : 인터셉트 개발부+인천인 애들만! 출력

	SELECT name, city, dept FROM emp WHERE dept = '개발부' 
	INTERSECT
	SELECT name, city, dept FROM emp WHERE city = '인천'