工作日計算問題思路和實現

CREATE TABLE [dbo].[holiday](
	[begin_time] [varchar](50) NULL,
	[end_time] [varchar](50) NULL
) ON [PRIMARY]

GO

declare @query_begin datetime --查詢起始時間
declare @query_end datetime --查詢結束時間
declare @year1 int 
declare @year2 int
declare @yeartemp int
declare @total_holidays int
set @query_begin = '2014-09-01'
set @query_end = '2015-01-31'
set @year1 = YEAR(@query_begin)
set @year2 = YEAR(@query_end)

--存儲所有的含有年月日的假期
IF object_id('tempdb..#temp') is not null
 BEGIN
 drop table #temp
 END
 CREATE table #temp
 (
 begin_time date, 
 end_time date, 
 )

insert into #temp
select convert(varchar(4),@year1)+'-'+begin_time, convert(varchar(4),@year1)+'-'+end_time 
from holiday

--這里主要考慮查詢時間段跨年的情況
set @yeartemp=@year1+1
while @yeartemp<=@year2
begin
 insert into #temp
 select convert(varchar(4),@yeartemp)+'-'+begin_time, convert(varchar(4),@yeartemp)+'-'+end_time 
 from holiday
 set @yeartemp=@yeartemp+1
end

--去掉和查詢時間段沒有一點交集的假日段
delete from #temp
where end_time<@query_begin or begin_time>@query_end

select @total_holidays= SUM(DATEDIFF(dd,begin_time,end_time)+1)
from
(
 select case when begin_time<@query_begin then @query_begin else begin_time end as begin_time,
 case when end_time>@query_end then @query_end else end_time end as end_time from #temp
) t 

select DATEDIFF(DD,@query_begin,@query_end)+1-@total_holidays

drop table #temp