WITH
 TBL(GUBUN,COMENT) AS (VALUES
 ('A','가나다')
,('A','라마바')
,('B','차카타')
,('B','파하가')
,('B','나다라')
,('C','마바사')
,('C','아자차')
)

SELECT  GUBUN
       ,MAX(CASE RN WHEN 1 THEN        COMENT ELSE '' END) ||
        MAX(CASE RN WHEN 2 THEN '+' || COMENT ELSE '' END) ||
        MAX(CASE RN WHEN 3 THEN '+' || COMENT ELSE '' END) ||
        MAX(CASE RN WHEN 4 THEN '+' || COMENT ELSE '' END) ||
        MAX(CASE RN WHEN 5 THEN '+' || COMENT ELSE '' END) COMENT
  FROM (
    SELECT  GUBUN ,COMENT
           ,ROW_NUMBER() OVER(PARTITION BY GUBUN) RN
--           ,ROW_NUMBER() OVER(PARTITION BY GUBUN ORDER BY COMENT) RN
      FROM  TBL
    ) T
 GROUP  BY  GUBUN