select
sum(T1.amount)+sum(T2.amount)
from
worktable t1,
worktable t2
where
t1.ac in ('a01', 'a02') and
t1.fl = '1' and
t2.ac in ('a03', 'a04') and
t2.fl = '2'

SELECT SUM(AMOUNT) as Result FROM worktable
WHERE (AC IN ('a01', 'a02') AND FL = 1) OR (AC IN ('a03', 'a04') AND FL = 2)

SELECT
	t1.ac,
	t3.amount / (t2.amount)

FROM acc t1,
	worktable t2,
	worktable t3
WHERE
	t3.fl = '3' and
	t3.ac = case t1.ac
		when 'b01' then 'a01'
		when 'b02' then 'a02'
		when 'b03' then 'a03'
		when 'b04' then 'a04' end  
	and
	(t2.ac IN ('a01', 'a02') AND t2.fl = 1) OR (t2.ac IN ('a03', 'a04') AND t2.fl = 2) GROUP BY t1.ac