[DATABASE/ORACLE] USE_HASH 힌트 : 해시 함수를 이용해 테이블 간 접근하기

■ USE_HASH 힌트를 사용해 해시 함수를 이용해 테이블 간 접근하는 방법을 보여준다.

▶ 예제 코드 (SQL)


SELECT /*+ USE_HASH(B) */
    A.DEPARTMENT_NAME
   ,A.DEPARTMENT_ID
   ,SUM(B.SALES_AMOUNT)
FROM  DEPARTMENT A, SALES B
WHERE A.DEPARTMENT_ID = B.DEPARTMENT_ID
AND   A.BUSINESS_NAME = '가전사업부'
AND   B.SALES_YM      = '202001'
GROUP BY
    A.DEPARTMENT_NAME
   ,A.DEPARTMENT_ID

SELECT /*+ USE_HASH(B) */

A.DEPARTMENT_NAME

,A.DEPARTMENT_ID

,SUM(B.SALES_AMOUNT)

FROM DEPARTMENT A, SALES B

WHERE A.DEPARTMENT_ID = B.DEPARTMENT_ID

AND A.BUSINESS_NAME = '가전사업부'

AND B.SALES_YM = '202001'

GROUP BY

A.DEPARTMENT_NAME

,A.DEPARTMENT_ID

※ /*+ USE_HASH(테이블명 [테이블명 …]) */