[프로그래머스/SQL]조건에 맞는 사용자 정보 조회하기

sol 1. join을 활용한 풀이

SELECT a.user_id,a.nickname,concat(a.city,' ',a.street_address1,' ', a.street_address2) 전체주소, concat(substr(tlno,1,3),'-',substr(tlno,4,4),'-',substr(tlno,8,4)) 전화번호
from used_goods_user a
inner join (
select writer_id, count(*) cnt
from used_goods_board 
group by writer_id
having cnt>=3) b on b.writer_id=a.user_id
order by user_id desc

sol 2. 서브쿼리를 사용한 풀이

SELECT  USER_ID
        ,NICKNAME
        ,CONCAT(CITY,' ',STREET_ADDRESS1,' ',STREET_ADDRESS2) AS 전체주소
        ,CONCAT(SUBSTRING(TLNO,1,3),'-',SUBSTRING(TLNO,4,4),'-',SUBSTRING(TLNO,8,4)) AS 전화번호
  FROM  USED_GOODS_USER
 WHERE  USER_ID IN(
         SELECT  WRITER_ID
          FROM  USED_GOODS_BOARD
         GROUP BY  WRITER_ID
        HAVING  COUNT(BOARD_ID) >= 3)
 ORDER
    BY  USER_ID DESC
;