tsql比较两个时间之间的工作时间

我在这个网址http://beyondrelational.com/blogs/tc/archive/2009/02/27/tsql-challenge-2.aspx发现了这个tsql 的challenge。要求计算两个给点时间之间的工作时间，假定工作日的时间是从早上8点到到下午5点。

很显然，周末的时间不能计算在工作时间内。

题目给定了假设数据时：

ID          StartDate               EndDate
----------- ----------------------- -----------------------
1           2009-03-02 08:00:00.000 2009-03-02 15:00:00.000
2           2009-03-01 16:00:00.000 2009-03-03 14:00:00.000
3           2009-02-26 07:00:00.000 2009-02-26 22:00:00.000
4           2009-01-27 09:15:00.000 2009-01-27 17:15:00.000
5           2009-01-17 13:45:00.000 2009-01-19 07:45:00.000
6           2009-01-27 21:15:00.000 2009-01-28 09:15:00.000

应该得到的结果是：

StartDate               EndDate                 Hours       Minutes 
----------------------- ----------------------- ----------- ----------- 
2009-03-02 08:00:00.000 2009-03-02 15:00:00.000 7           0 
2009-03-01 16:00:00.000 2009-03-03 14:00:00.000 15          0 
2009-02-26 07:00:00.000 2009-02-26 22:00:00.000 9           0 
2009-01-27 09:15:00.000 2009-01-27 17:15:00.000 7           45 
2009-01-17 13:45:00.000 2009-01-19 07:45:00.000 0           0 
2009-01-27 21:15:00.000 2009-01-28 09:15:00.000 1           15

下面是我的解决方案：

set datefirst 1;
with cte1(id, startDate, endDate) as(
	select 1, cast('2009-03-02 08:00:00.000' as datetime), cast('2009-03-02 15:00:00.000' as datetime) union all
	select 2, CAST('2009-03-01 16:00:00.000' as datetime), CAST('2009-03-03 14:00:00.000' as datetime) union all
	select 3, CAST('2009-02-26 07:00:00.000' as datetime), CAST('2009-02-26 22:00:00.000' as datetime) union all
	select 4, CAST('2009-01-27 09:15:00.000' as datetime), CAST('2009-01-27 17:15:00.000' as datetime) union all
	select 5, CAST('2009-01-17 13:45:00.000' as datetime), CAST('2009-01-19 07:45:00.000' as datetime) union all
	select 6, CAST('2009-01-27 21:15:00.000' as datetime), CAST('2009-01-28 09:15:00.000' as datetime)
)

--soluton 3
select id, startDate, endDate, SUM(case when minutes> 0 then minutes else 0 end) / 60 as hours,
	SUM(case when minutes> 0 then minutes else 0 end)  % 60 as minutes
from
(
	select *, isWeekday * DATEDIFF(minute, propStartDate, propEndDate) as minutes
	from (
		select *, 
			case DATEPART(weekday,  inStartDate) 
				when 6 then 0
				when 7 then 0
				else 1 end as isWeekday,
			case 
				when N=1 and startDate < inStartDate then inStartDate
				when N=1 and startDate > inStartDate then startDate
				else inStartDate end as propStartDate,
			case 
				when DATEDIFF(day, inEndDate, endDate) = 0 and endDate < inEndDate then endDate
				when DATEDIFF(day, startDate, endDate) = 0 and endDate >= inEndDate then inEndDate
				else inEndDate end as propEndDate
		from (
			select *, dateadd(day, N-1, DATEADD(hour,8, DATEADD(day,DATEDIFF(day, 0, startDate), 0))) as inStartDate,
				dateadd(day, N-1, DATEADD(hour, 17, DATEADD(day,DATEDIFF(day, 0, startDate), 0))) as inEndDate	
			from cte1 c1 cross apply(
				select *
				from dbo.Number
				where N <= DATEDIFF(day, c1.startDate, c1.endDate) + 1) as c
		) as d
	) as d2
) as d3

group by id, startDate, endDate

结果如下：