select a.CHECKUP_DATE as CK_DATE,
a.MEMBER_CODE as CODE,
c.LAST_NAME || c.FIRST_NAME as NAME,
round(cast(a.WEIGHT as REAL) - cast(b.WEIGHT as REAL),1) AS CHG_WT
from 
( select
 *
 from
 (
   select
   CHECKUP_DATE
  ,MEMBER_CODE
  ,WEIGHT
  ,row_number() over (partition by MEMBER_CODE order by CHECKUP_DATE desc) as rank
   from
   HEALTH_CHECKUP
 )
 where
 rank = 1) a,
(  select
 *
 from
 (
   select
   CHECKUP_DATE
  ,MEMBER_CODE
  ,WEIGHT
  ,row_number() over (partition by MEMBER_CODE order by CHECKUP_DATE desc) as rank
   from
   HEALTH_CHECKUP
 )
 where rank = 2 ) b,
MEMBER_MST c
 where a.MEMBER_CODE = b.MEMBER_CODE
 and a.MEMBER_CODE = c.MEMBER_CODE
 and abs(round(cast(a.WEIGHT as REAL) - cast(b.WEIGHT as REAL),1)) >=5
order by 4 desc,2 desc