断号表查询，断号表的数据，通过查询，找出断号后的第一个值

Question

使用oracle的sql语句实现，怎么做？

N1

---

4
5
6
7
9
10
13
14
15

要得到如下结果

N1

4
9
13

Answer 1

select case when leag(n1,1,0) over(order by n1) - n1 >1
then leag(n1,1,0) over(order by n1)
when rowid = (select min(rowid) from tablename)
then n1
end
from tablename
;

未测试，应该能行