select
t1.checkup_date as CK_DATE,
t1.member_code as CODE,
t3.last_name || t3.first_name as NAME,
round(t1.weight -t2.weight,1)as CHG_WT
from health_checkup as t1
left join health_checkup as t2
on t1.member_code = t2.member_code
and t1.checkup_date < t2.checkup_date
left join member_mst as t3
on t1.member_code = t3.member_code