질문이 모호하네요.

원본 데이터와 원하는 데이터를 올려주세요.

Select sid, listagg(mid,',') within group ( order by mid) mid_lis

From 테이블

group by sid

이런것을 원하시는건가요?

DB는 postgreSql에서 실행했습니다

  원한는결과가 맞는건가요?

with SIDMID (SID,MID) as (
 SELECT 'SID1',  'MID1'  UNION ALL
 SELECT 'SID1',  'MID2'  UNION ALL
 SELECT 'SID1',  'MID3'  UNION ALL
 SELECT 'SID2',  'MID4'  UNION ALL
 SELECT 'SID2',  'MID5'  UNION ALL
 SELECT 'SID3',  'MID6'  UNION ALL
 SELECT 'SID3',  'MID7' 
)

SELECT sid, string_agg(mid,',') FROM SIDMID
GROUP BY SID
ORDER BY 1
;



--결과 :


SID         |      MID


SID1          MID1,MID2,MID3
SID2          MID4,MID5
SID3          MID6,MID7

  SELECT SID, LISTAGG (MID, ',') WITHIN GROUP (ORDER BY MID) MID_LIS
    FROM (SELECT 'SID1' AS SID, 'MID1' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID1' AS SID, 'MID2' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID1' AS SID, 'MID3' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID2' AS SID, 'MID4' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID2' AS SID, 'MID5' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID3' AS SID, 'MID6' AS MID FROM DUAL
          UNION ALL
          SELECT 'SID3' AS SID, 'MID7' AS MID FROM DUAL)
GROUP BY SID