[Oracle] 조건에 맞는 사용자와 총 거래금액 조회하기

https://school.programmers.co.kr/learn/courses/30/lessons/164668

프로그래머스

정답

SELECT B.USER_ID, B.NICKNAME, SUM(A.PRICE) AS TOTAL_SALES 
FROM USED_GOODS_BOARD A
	JOIN USED_GOODS_USER B ON A.WRITER_ID = B.USER_ID
WHERE A.STATUS = 'DONE'
GROUP BY B.USER_ID, B.NICKNAME
HAVING SUM(A.PRICE) >= 700000
ORDER BY TOTAL_SALES ;

풀이

Step 1) Group by

SELECT B.USER_ID, B.NICKNAME AS TOTAL_SALES 
FROM USED_GOODS_BOARD A INNER JOIN USED_GOODS_USER B 
    ON A.WRITER_ID = B.USER_ID
WHERE A.STATUS = 'DONE'
;

step 1-1 ) user_id,total_sales 요약하기

SELECT B.USER_ID, B.NICKNAME,sum(A.price) AS TOTAL_SALES 
FROM USED_GOODS_BOARD A INNER JOIN USED_GOODS_USER B 
    ON A.WRITER_ID = B.USER_ID
WHERE A.STATUS = 'DONE'
GROUP BY B.USER_ID, B.NICKNAME
;

요약되서 total_sales 에서 합계

step2 ) Having 으로 group by 조건 붙히기

SELECT B.USER_ID, B.NICKNAME,sum(A.price) AS TOTAL_SALES 
FROM USED_GOODS_BOARD A INNER JOIN USED_GOODS_USER B 
    ON A.WRITER_ID = B.USER_ID
WHERE A.STATUS = 'DONE'
GROUP BY B.USER_ID, B.NICKNAME
HAVING SUM(A.PRICE) >= 700000
;