select
CK_DATE
,CODE
,NAME
,CHG_WT
from
(
select
  row_number() over(partition by main.MEMBER_CODE order by CHECKUP_DATE desc) as CK_DESC_NUM
 ,FIRST_VALUE(CHECKUP_DATE) over(partition by main.MEMBER_CODE order by CHECKUP_DATE desc) as CK_DATE
 ,main.MEMBER_CODE as CODE
 ,mst.LAST_NAME || mst.FIRST_NAME as NAME
 ,round(main.WEIGHT - lead(main.WEIGHT) over(partition by main.MEMBER_CODE order by CHECKUP_DATE desc), 3) as CHG_WT
from
    HEALTH_CHECKUP as main
inner join
    MEMBER_MST as mst using(MEMBER_CODE)
)
 where
     CK_DESC_NUM = 1
     and (CHG_WT > 4.999 or  CHG_WT < -4.999 )
order by
     CHG_WT desc
    ,CODE desc