SQL计算问题 - MS-SQL Server / 疑难问题

SELECT a.线别, a.工单, a.型号, a.工单量, a.计划小时产量, a.联板数量, a.锡膏批号, a.目标良率, a.站位, a.完成时间, a.计划用时, a.机器用时, 
  计算用时 = isnull(cast(datediff(SS, a.完成时间, b.完成时间) AS int), ''), 差异 = isnull(cast(datediff(SS, a.完成时间, b.完成时间) AS int), '') - a.计划用时, 
  a.抛料数量, a.id
from (SELECT idd = row_number() OVER (ORDER BY 完成时间), *
from SmtResultReport1) a LEFT JOIN
  (SELECT idd = row_number() OVER (ORDER BY 完成时间), *
from SmtResultReport1) b ON a.idd = b.idd - 1


语句如上：

上面的结果已经是我要的结果的了，结果假设如下：


列1 列2 列3
a 2010-05-08 15:30:30.100 1
b 2010-05-08 15:31:30.100 1
c 2010-05-08 15:32:30.100 1
d 2010-05-08 15:33:30.100 0

我想改成如下结果:

列1 列2 列3
a 2010-05-08 15:30:30.100 0
b 2010-05-08 15:31:30.100 1
c 2010-05-08 15:32:30.100 1
d 2010-05-08 15:33:30.100 1

请问上面的语句应该怎么改？谢谢！

---

SQL code:
SELECT a.线别, a.工单, a.型号, a.