select 
    I.ITEM_CODE ITEM
    , I.ITEM_NAME I_NAME
    , C.CL_NAME C_NAME
    , S.SIZE_NAME S_NAME
from 
    ITEM I
left outer join 
    COLOR_TBL C
on
    I.ITEM_CODE = C.CL_CODE
left outer join
    SIZE_TBL S
on
    C.UPDATE_USER_NAME = S.UPDATE_USER_NAME
where
    I.STOCK_MANAGEMENT_TYPE = 1
order by
    ITEM_CODE, CL_NAME, SIZE_NAME