[Algorithm /프로그래머스] 조건에 맞는 사용자 정보 조회하기

[문제 설명]
다음은 중고 거래 게시판 정보를 담은 USED_GOODS_BOARD 테이블과 중고 거래 게시판 첨부파일 정보를 담은 USED_GOODS_USER 테이블입니다. USED_GOODS_BOARD 테이블은 다음과 같으며 BOARD_ID, WRITER_ID, TITLE, CONTENTS, PRICE, CREATED_DATE, STATUS, VIEWS는 게시글 ID, 작성자 ID, 게시글 제목, 게시글 내용, 가격, 작성일, 거래상태, 조회수를 의미합니다.

Column name Type Nullable
BOARD_ID VARCHAR(5) FALSE
WRITER_ID VARCHAR(50) FALSE
TITLE VARCHAR(100) FALSE
CONTENTS VARCHAR(1000) FALSE
PRICE NUMBER FALSE
CREATED_DATE DATE FALSE
STATUS VARCHAR(10) FALSE
VIEWS NUMBER FALSE
USED_GOODS_USER 테이블은 다음과 같으며 USER_ID, NICKNAME, CITY, STREET_ADDRESS1, STREET_ADDRESS2, TLNO는 각각 회원 ID, 닉네임, 시, 도로명 주소, 상세 주소, 전화번호를 의미합니다.

Column name Type Nullable
USER_ID VARCHAR(50) FALSE
NICKANME VARCHAR(100) FALSE
CITY VARCHAR(100) FALSE
STREET_ADDRESS1 VARCHAR(100) FALSE
STREET_ADDRESS2 VARCHAR(100) TRUE
TLNO VARCHAR(20) FALSE


[문제]
USED_GOODS_BOARD와 USED_GOODS_USER 테이블에서 중고 거래 게시물을 3건 이상 등록한 사용자의 사용자 ID, 닉네임, 전체주소, 전화번호를 조회하는 SQL문을 작성해주세요. 이때, 전체 주소는 시, 도로명 주소, 상세 주소가 함께 출력되도록 해주시고, 전화번호의 경우 xxx-xxxx-xxxx 같은 형태로 하이픈 문자열(-)을 삽입하여 출력해주세요. 결과는 회원 ID를 기준으로 내림차순 정렬해주세요.

[문제 해결 - 조인]

SELECT 
    T1.USER_ID AS USER_ID
    , UGU.NICKNAME AS NICKNAME
    ,  UGU.CITY|| ' ' || UGU.STREET_ADDRESS1 ||' '|| UGU.STREET_ADDRESS2 AS "전체주소"
    , SUBSTR(UGU.TLNO,0,3) || '-' 
        || SUBSTR(UGU.TLNO,4,4) || '-'  || SUBSTR(UGU.TLNO,8,4)
         AS "전화번호"
    FROM (
    SELECT
     UGB.WRITER_ID AS USER_ID
        ,COUNT(*) AS CNT
    FROM
    USED_GOODS_BOARD UGB
    GROUP BY UGB.WRITER_ID
) T1
INNER JOIN USED_GOODS_USER UGU
ON T1.CNT >=3
AND T1.USER_ID = UGU.USER_ID
ORDER BY T1.USER_ID DESC

 

 

[문제 해결 - 서브 쿼리]

SELECT
    USER_ID
    , NICKNAME
    , CITY || ' '||STREET_ADDRESS1 ||' '|| STREET_ADDRESS2 AS 전체주소
    , SUBSTR(TLNO,0,3) || '-'||SUBSTR(TLNO,4,4) ||'-'||SUBSTR(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