집합연산자, 집단연산자

set operator.sql

@@ -0,0 +1,51 @@
+USE Study
+GO
+
+(SELECT * FROM EMPLOYEE WHERE DNO = 10)
+UNION
+(SELECT * FROM EMPLOYEE WHERE JOB = 'chief')
+
+(SELECT * FROM EMPLOYEE WHERE DNO = 10)
+INTERSECT
+(SELECT * FROM EMPLOYEE WHERE JOB = 'chief')
+
+(SELECT * FROM EMPLOYEE WHERE DNO = 10)
+EXCEPT
+(SELECT * FROM EMPLOYEE WHERE JOB = 'chief')
+
+-- 중복 허용 합집합
+(SELECT * FROM EMPLOYEE WHERE DNO = 10)
+UNION ALL
+(SELECT * FROM EMPLOYEE WHERE JOB = 'chief')
+
+-- 외부 합집합 (합병 호환성[: 속성 개수 및 타입 일치] 불일치 할 때)
+(SELECT ENO, ENAME, DNO, NULL FROM EMPLOYEE)
+UNION
+(SELECT NULL, NULL, DNO, DNAME FROM DEPARTMENT)
+
+-- 집단 연산자
+SELECT AVG(SALARY) FROM EMPLOYEE
+
+SELECT MAX(SALARY) AS MAXSALARY, MIN(SALARY) AS MINSALARY FROM EMPLOYEE
+
+SELECT AVG(SALARY) AS AVERAGE, VAR(SALARY) AS VARIANCE, STDEV(SALARY) AS STANDARDDEVIATION FROM EMPLOYEE
+
+SELECT * FROM EMPLOYEE
+SELECT COUNT(*) AS NUMROW, COUNT(COMMISSION) FROM EMPLOYEE
+
+SELECT * FROM EMPLOYEE
+SELECT COUNT(JOB) AS JOB, COUNT(DISTINCT JOB) AS DISTJOB FROM EMPLOYEE
+
+SELECT DNO, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY DNO
+
+SELECT DNO, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY DNO HAVING MAX(SALARY) > 500
+
+SELECT DNO, JOB, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY DNO, JOB ORDER BY DNO
+
+SELECT DNO, JOB, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY DNO, JOB WITH ROLLUP
+
+SELECT DNO, JOB, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY DNO, JOB WITH CUBE
+
+SELECT DNO, JOB, AVG(SALARY) AS AVGSAL FROM EMPLOYEE GROUP BY GROUPING SETS (DNO, JOB) -- DNO, JOB 따로 한 것을 UNION 해서 보여줌
+
+