select 
    i.ITEM_CODE AS ITEM,
    i.ITEM_NAME AS I_NAME,
    ct.CL_NAME AS C_NAME,
    st.SIZE_NAME AS S_NAME
FROM
    ITEM AS i
LEFT OUTER JOIN
    COLOR_TBL AS ct
    ON
        ct.UPDATE_USER_NAME = i.UPDATE_USER_NAME
LEFT OUTER JOIN
    SIZE_TBL AS st
    ON
        st.UPDATE_USER_NAME = i.UPDATE_USER_NAME   
;