SH

https://school.programmers.co.kr/learn/courses/30/lessons/164668 WRITER_ID와 USER_ID가 외래키라는 명시가 없었다. 하지만, 조인이 가능한 속성임이 유일했다. SELECT B.WRITER_ID, U.NICKNAME, SUM(B.PRICE) TOTAL_SALESFROM USED_GOODS_BOARD B JOIN USED_GOODS_USER UON B.WRITER_ID = U.USER_IDWHERE B.STATUS LIKE 'DONE'GROUP BY B.WRITER_IDHAVING TOTAL_SALES >= 700000ORDER BY TOTAL_SALES

https://school.programmers.co.kr/learn/courses/30/lessons/131118SELECT REST_ID, REST_NAME, FOOD_TYPE, FAVORITES, ADDRESS, ROUND(SCORE, 2) SCOREFROM (SELECT I.REST_ID, REST_NAME, FOOD_TYPE, FAVORITES, ADDRESS, SCORE FROM REST_INFO I JOIN (SELECT REST_ID, AVG(REVIEW_SCORE) SCORE FROM REST_REVIEW GROUP BY REST_ID) AS RON I.REST_ID = R.RE..