sql - 如何获取范围内一年中特定月份的天数总和

Question

如果我有具有以下结构的假期表:

emp_num start_date   end_date
 234     8-2-2015    8-5-2015
 234     6-28-2015   7-1-2015
 234     8-29-2015   9-2-2015
 115     6-7-2015    6-7-2015
 115     8-7-2015    8-10-2015

考虑日期格式为:m/dd/yyyy

我怎样才能获得每个员工在特定月份的假期总和。

假设我想在8Aug-2015 获得假期

我想要这样的结果

emp_num   sum
234        7
115        4

7 = 8-2-2015 和 8-5-2015 之间的所有日期 加上 8-29 之间的所有日期-2015 和 8-31-2015 月底

Answer 1

希望这对你有帮助

declare @temp table
(emp_num int, startdate date, enddate date)


 insert into @temp values (234,'8-2-2015','8-5-2015')
 insert into @temp values (234,'6-28-2015','7-1-2015')
 insert into @temp values (234,'8-29-2015','9-2-2015')
 insert into @temp values (115,'6-7-2015','6-7-2015')
 insert into @temp values (115,'8-7-2015','8-10-2015')
-- i am passing 8 as month number in your case is August
 select emp_num,
 SUM(
 DATEDIFF (DAY , startdate,  
 case when MONTH(enddate) = 8
            then enddate
            else DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,startdate)+1,0))--end date of month
            end
 )+1) AS Vacation from @temp
 where (month(startdate) = 8 OR month(enddate) = 8) AND (Year(enddate)=2015 AND Year(enddate)=2015)
 group by emp_num

更新有效评论后:此操作将在以下日期失败:2015-07-01、2015-09-30 –@t-clausen.dk
我以为OP只想要一个月，他会通过

declare @temp table
(emp_num int, startdate date, enddate date)


 insert into @temp values (234,'8-2-2015','8-5-2015')
 insert into @temp values (234,'6-28-2015','7-1-2015')
 insert into @temp values (234,'8-29-2015','9-2-2015')
 insert into @temp values (115,'6-7-2015','6-7-2015')
 insert into @temp values (115,'8-7-2015','8-10-2015')

 insert into @temp values (116,'07-01-2015','9-30-2015')


 select emp_num,
 SUM(
 DATEDIFF (DAY , startdate,  
 case when MONTH(enddate) = 8 
            then enddate
            else DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,startdate)+1,0))
            end
 )+1) AS Vacation from @temp
 where (Year(enddate)=2015 AND Year(enddate)=2015) 
 AND 8 between MONTH(startdate) AND MONTH(enddate)
 group by emp_num