seq=1是收入，后面是支出，那么可以用case when把后面的数变为负数

with x as
 (select rownum as seq, a.*
    from (select 编号, 项目, 金额 from detail order by 编号) a)
select 编号,
       项目,
       金额(case
            when seq = 1 then
             金额
            else
             -金额
          end) as 转换后的值,
       sum(case
             when seq = 1 then
              金额
             else
              -金额
           end) over(order by seq) as 余额
  from x;