GREATEST 오라클 함수 [Oracle, Pandas, R Prog, Dplyr, Sqldf, Pandasql, Data.Table, DuckDB]

* 파이썬 & R 패키지 호출 및 예제 데이터 생성 링크

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[ GREATEST Oracle Function ]

 

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GREATEST함수는 하나 이상의 인수중에서 가장 큰 값을 반환한다.

 

• 함수 설명 : GREATEST 오라클 함수 링크

 

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1. Oracle(오라클)

 

Oracle Programming

SELECT GREATEST ('HARRY', 'HARRIOT', 'HAROLD') "Greatest"
FROM   DUAL;

 

Results

Greatest
--------------
HARRY

 

 

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2. Python Pandas(파이썬)

 

Python Programming

max('HARRY', 'HARRIOT', 'HAROLD')

 

 

Results

'HARRY'

 

 

 

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3. R Programming (R Package)

 

R Programming

%%R

max('HARRY', 'HARRIOT', 'HAROLD')

 

 

Results

[1] "HARRY"

 

 

 

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4. R Dplyr Package

 

R Programming

%%R

emp %>%
  rowwise() %>%
  dplyr::mutate(Greatest = max(ename, job)) %>%
  head(10)

 

 

Results

# A tibble: 10 x 9
# Rowwise: 
   empno ename  job         mgr hiredate     sal  comm deptno Greatest 
   <dbl> <chr>  <chr>     <dbl> <date>     <dbl> <dbl>  <dbl> <chr>    
 1  7369 SMITH  CLERK      7902 1980-12-17   800    NA     20 SMITH    
 2  7499 ALLEN  SALESMAN   7698 1981-02-20  1600   300     30 SALESMAN 
 3  7521 WARD   SALESMAN   7698 1981-02-22  1250   500     30 WARD     
 4  7566 JONES  MANAGER    7839 1981-04-02  2975    NA     20 MANAGER  
 5  7654 MARTIN SALESMAN   7698 1981-09-28  1250  1400     30 SALESMAN 
 6  7698 BLAKE  MANAGER    7839 1981-03-01  2850    NA     30 MANAGER  
 7  7782 CLARK  MANAGER    7839 1981-01-09  2450    NA     10 MANAGER  
 8  7788 SCOTT  ANALYST    7566 1982-12-09  3000    NA     20 SCOTT    
 9  7839 KING   PRESIDENT    NA 1981-11-17  5000    NA     10 PRESIDENT
10  7844 TURNER SALESMAN   7698 1981-09-08  1500     0     30 TURNER   

 

 

 

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5. R sqldf Package

 

R Programming

%%R

sqldf(" SELECT max('HARRY', 'HARRIOT', 'HAROLD') Greatest   ")

 

 

Results

  Greatest
1    HARRY

 

 

 

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6. Python pandasql Package

 

Python Programming

ps.sqldf("  SELECT max('HARRY', 'HARRIOT', 'HAROLD') Greatest ")

 

 

Results

	Greatest
0	HARRY

 

 

 

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7. R data.table Package

 

행 단위 연산을 위하여 그룹 변수에 Seq를 지정

 

R Programming

%%R

DT          <- data.table(emp)
dept_DT     <- data.table(dept)

DT[, Greatest := max(ename, job), by=1:nrow(DT)][1:7, ]

 

 

Results

   empno  ename      job  mgr   hiredate  sal comm deptno Greatest
1:  7369  SMITH    CLERK 7902 1980-12-17  800   NA     20    SMITH
2:  7499  ALLEN SALESMAN 7698 1981-02-20 1600  300     30 SALESMAN
3:  7521   WARD SALESMAN 7698 1981-02-22 1250  500     30     WARD
4:  7566  JONES  MANAGER 7839 1981-04-02 2975   NA     20  MANAGER
5:  7654 MARTIN SALESMAN 7698 1981-09-28 1250 1400     30 SALESMAN
6:  7698  BLAKE  MANAGER 7839 1981-03-01 2850   NA     30  MANAGER
7:  7782  CLARK  MANAGER 7839 1981-01-09 2450   NA     10  MANAGER

 

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8. Python DuckDB의 SQL

 

Python Programming

%%sql
  SELECT GREATEST ('HARRY', 'HARRIOT', 'HAROLD') as "Greatest"

 

Python Programming

duckdb.sql(" SELECT GREATEST ('HARRY', 'HARRIOT', 'HAROLD') as Greatest_1 ").df()

 

 

Results

  Greatest_1
0      HARRY

 

 

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[Oracle, Pandas, R Prog, Dplyr, Sqldf, Pandasql, Data.Table] 오라클 함수와 R & Python 비교 사전 목록? 링크

 

오라클 SQL 함수(Oracle SQL Function) 목록 리스트 링크

 

[SQL, Pandas, R Prog, Dplyr, SQLDF, PANDASQL, DATA.TABLE] SQL EMP 예제로 만나는 테이블 데이터 처리 방법 리스트 링크 링크