🟦 게시물 디테일 - 댓글이 여러개인데도 하나만 나온다.

🔹 에러

🔹 원인

✅ GROUP BY 하지 않았기 떄문

SELECT A.cmt_id, A.feed_id, A.users_id, A.cmt_cmt, A.cmt_regdt
             , B.users_img, B.users_nickname
            <if test="user4FavCmt > 0">
            , CASE WHEN COUNT(C.users_id) IS NULL THEN 0 END AS cmtFavCnt  👈🔺틀리게 적음🔺
            , CASE WHEN D.users_id IS NULL THEN 0 ELSE 1 END AS isCmtFav
            </if>
        FROM cmt A
        LEFT JOIN users B
        ON A.users_id = B.users_id
        <if test="user4FavCmt > 0">
        LEFT JOIN cmt_fav C  👈🔺GROUP BY 해야한다🔺
        ON C.cmt_id = A.cmt_id AND C.feed_id = A.feed_id
        LEFT JOIN cmt_fav D 👈🔺GROUP BY 해야한다🔺
        ON D.cmt_id = A.cmt_id AND D.feed_id = A.feed_id AND D.users_id = ${user4FavCmt}
        </if>
        WHERE A.feed_id = ${feed_id}
        ORDER BY A.feed_id DESC

👇올바른 SQL

SELECT A.cmt_id, A.feed_id, A.users_id, A.cmt_cmt, A.cmt_regdt
             , B.users_img, B.users_nickname
        
            , IFNULL(C.cnt, 0) AS cmtFavCnt 👈🔺수정🔺
            , CASE WHEN D.users_id IS NULL THEN 0 ELSE 1 END AS isCmtFav
        
        FROM cmt A
        LEFT JOIN users B
        ON A.users_id = B.users_id
        
        LEFT JOIN (                      👈🔺GROUP BY🔺
        SELECT cmt_id, feed_id, COUNT(cmt_id) AS cnt
		  FROM cmt_fav
		  GROUP BY cmt_id
		  ) C
        ON C.cmt_id = A.cmt_id AND C.feed_id = A.feed_id
        LEFT JOIN (             👈🔺GROUP BY🔺
		  SELECT cmt_id, feed_id, users_id
		  FROM cmt_fav
		  GROUP BY cmt_id
		  ) D
        ON D.cmt_id = A.cmt_id AND D.feed_id = A.feed_id AND D.users_id = 2
        WHERE A.feed_id = 3
        ORDER BY A.feed_id DESC