SQL 정리하기

SELECT [ Column or Expression ]

FROM [ Table or View ]

WHERE 원하는 조건 ;

DISTINCT

BETWEEN 'A' AND 'B'    

GROUP BY

select deptno , job , avg(nvl(sal,0)) "avg" 

from emp 

group by deptno, job ;

deptno 도 맞으면서 job 같은 집합의 급여 평균 

Having 이 추가되서 좀더 세부적인 검색이 가능함 

select deptno , job , avg(nvl(sal,0)) "avg" from emp group by deptno, job ;

select deptno , job , avg(nvl(sal,0)) "avg" from emp group by deptno, job                     having avg(nvl(sal,0)) >2000;