select a.bank1,a.bank2, a.money-b.money money from (select bank1,bank2,sum(money) money from tab group by bank1,bank2) a,(select bank1,bank2,sum(money) money from tab group by bank1,bank2) b where a.bank1=b.bank2 and a.bank2=b.bank1
调试欢乐多
least(bank1, bank2) bank2,
sum(decode(bank1, greatest(bank1, bank2), money, -money)) money
from tablename
group by greatest(bank1, bank2), least(bank1, bank2)