ranking

first_value, lag, lead.sql

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+USE Study
+GO
+
+-- 행순서 함수
+
+-- FISRT_VALUE: 첫번째 튜플만
+SELECT DISTINCT DNO, FIRST_VALUE(SALARY) OVER (PARTITION BY DNO ORDER BY SALARY DESC) AS HIGH_SALARY
+FROM EMPLOYEE
+
+-- LAG/LEAD: 정렬 기준 선행/후행 값 출력
+SELECT 
+	DISTINCT ENAME, 
+	SALARY, 
+	LAG(SALARY, 1) OVER(ORDER BY SALARY DESC) AS LAG_SALARY,
+	LEAD(SALARY, 1) OVER(ORDER BY SALARY DESC) AS LEAD_SALARY
+FROM EMPLOYEE

group rank (partition by).sql

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+USE Study
+GO
+
+-- 그룹별 순위 지정
+SELECT ENAME, SALARY, DNO, RANK() OVER (PARTITION BY DNO ORDER BY SALARY DESC) AS RANK_DEPT
+FROM EMPLOYEE
+
+-- 각 그룹 급여기준 2위인 사원의 부서정보, 이름, 급여, 순위 조회
+SELECT *
+FROM 
+	(SELECT DNO, ENAME, SALARY, RANK() OVER (PARTITION BY DNO ORDER BY SALARY DESC) AS RANK_VALUE
+	FROM EMPLOYEE) AS TEMP
+WHERE RANK_VALUE = 2
+
+-- 그룹별 집단 함수 사용
+SELECT DISTINCT DNO, AVG(SALARY) OVER (PARTITION BY DNO) FROM EMPLOYEE
+SELECT DISTINCT DNO, AVG(SALARY) FROM EMPLOYEE GROUP BY DNO

top rank.sql

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+USE Study
+GO
+
+-- TOP
+
+SELECT TOP(5) * FROM EMPLOYEE ORDER BY SALARY DESC
+
+SELECT TOP(5) WITH TIES * FROM EMPLOYEE ORDER BY SALARY DESC
+
+SELECT TOP(20) PERCENT * FROM EMPLOYEE ORDER BY SALARY DESC
+
+SELECT TOP(5) * FROM EMPLOYEE ORDER BY SALARY DESC
+
+
+-- RANK
+SELECT ENAME, SALARY, RANK() OVER (ORDER BY SALARY DESC) AS SALRANK FROM EMPLOYEE
+
+SELECT ENAME, SALARY, DENSE_RANK() OVER (ORDER BY SALARY DESC) AS SALDENSERANK FROM EMPLOYEE
+
+SELECT ENAME, SALARY, ROW_NUMBER() OVER (ORDER BY SALARY DESC) AS SALROWRANK FROM EMPLOYEE
+
+SELECT ENAME, SALARY, NTILE(5) OVER (ORDER BY SALARY DESC) AS RANKNTILE FROM EMPLOYEE