Select Doff_No,
        SL_BR,
        LTRIM(Max(SYS_CONNECT_BY_PATH(output_code,',')),',')
        ,Count(1)
From (
  SELECT ROW_NUMBER() OVER ( PARTITION BY Doff_No,
  SubStr(SL_BR,2,1)
  ORDER BY Doff_No,
  SubStr(SL_BR,2,1) ) Rn,
  Doff_No,
  SubStr(SL_BR,2,1) SL_BR,
  output_code
  From SL_ActualRoll
  Where Doff_No Like 'J182%'
  and OutPut_Code is not Null
)
Where SL_BR is Not Null

Start With Rn = 1
CONNECT bY Prior Doff_NO = DOFF_NO /* 그룹 걸넘들이 다 and로 묶어야 한다. */
       And Prior SL_Br = SL_BR
       and Prior Rn = Rn - 1
Group By Doff_No, SL_BR