Zkuste použít merge
merge into table1 tab1
using
(
SELECT tab3.name, tab3."add", SUM(tab2.amount) AS total
FROM table2 tab2,
table3 tab3 ,
table4 tab4
WHERE tab2.id = tab3.id
AND tab3.id = tab4.id
AND tab4.indicator ='Y'
GROUP BY tab3.name,
tab3."add"
)t1
on(tab1.id = t1.id)
when matched then
update set tab1.total_adjusted_cost = tab1.total_adjusted_cost + t1.total