select to_char(a.学号+1,'0000')
from
(
select to_number(t.学号) 学号, to_number(lead(学号, 1, 0) OVER(ORDER BY 学号)) as ff from aaa t
) a
where
a.学号 != a.ff-1
and rownum=1
试试这个:
SELECT B.ID
FROM (
SELECT LTRIM(TO_CHAR(ROWNUM,'0000')) AS ID,A.PK
FROM(
SELECT PK FROM TABLE ORDER BY PK) A
) B
WHERE B.ID <> B.PK AND ROWNUM = 1