我有如下表

PK      num1   num2  numsdiff
1       10     15    ?
2       20     25    ?
3       30     35    ?
4       40     45    ?

我需要从这个表中选择查询得到20 – 15和30 – 25和40 – 35的减法等等.

有任何想法吗？.

谢谢

最佳答案

WITH    q AS
        (
        SELECT  *,
                ROW_NUMBER() OVER ORDER BY (num1) AS rn
        FROM    mytable
        )
SELECT  qc.*, qc.num1 - qp.num2
FROM    q qc
LEFT JOIN
        q qp
ON      qp.rn = qc.rn - 1