[oracle] 연결 연산자, 리터럴 문자열, 중복 행 제거

연결 연산자 

select LAST_NAME || JOB_ID as "EMPLOYEES" from EMPLOYEES;
 
결과
EMPLOYEES
-----------------
AbelSA_REP
AndeSA_REP
AtkinsonST_CLERK
AustinIT_PROG
BaerPR_REP

  

리터럴 문자열

select LAST_NAME || ' is a ' || JOB_ID as "EMPLOYEES" from EMPLOYEES;
 
결과
EMPLOYEES
----------------------
Abel is a SA_REP
Ande is a SA_REP
Atkinson is a ST_CLERK
Austin is a IT_PROG
Baer is a PR_REP

  

중복 행 제거

select DISTINCT DEPARTMENT_ID from EMPLOYEES;
 
결과
DEPARTMENT_ID
-------------
100
30
90
20
70