sql 中基于行数的行之间的差异(SQL 服务器)

Difference between rows in sql based on rows number (SQL Server)

我有问题。我有 table 以下列和示例数据:

RN   Date       Time     
---------------------
1  2015-02-02    12
2  2015-02-02    25
3  2015-02-02    27
1  2015-02-08    42
2  2015-02-08    45
1  2015-03-01    60
2  2015-03-01    62
3  2015-03-01    63
4  2015-03-01    63

我需要获取每天开始时间和结束时间之间的差异。

例如:

27-12
45-42
63-60

有什么建议吗? :)

select 
  Date, max(Time) as mx, min(Time) as mn, max(Time) - min(Time) as diff 
from table_name 
group by Date