Question

这就是表格的呈现方式

SELECT RequestsID, Country, Activity,
[People needed (each day)], [Start date], [End date]
FROM dbo.Requests

会有很多请求，我想总结每天“需要的人”（！），而不是在开始和结束日期之间。

此外，我想按国家/地区分组，并且可以设置我想要获取数据的日期。

对于需要的人（0），有些日子可能是空的，但无论如何都应该提供日期。请注意，可能有多个请求指出相同的日期和相同的国家/地区 - 但活动是不同的。

查询应该是（好吧，你可以看到它不是SQL，只是试图显示逻辑）

From Requests,
show Country and SUM 'People needed'
where (column not in Requests table-Date) is a Date (will be
a number of dates, I want to set the scope by a Start and End date)
and Requests.Country is @Country 
(and the Date(s) above of course is between the Requests Start date and End date...)
And from (a non existing table...?) show Date
Group by Country

我希望看到类似的内容：

Date            Country         People needed

06/01/2010      Nigeria          34 // this might be from three different Requests, all pointing out Nigeria. People needed might be (30+1+3 = 34)
06/02/2010      Nigeria          10
06/03/2010      Nigeria           0
06/04/2010      Nigeria           1
06/05/2010      Nigeria         134

06/01/2010      China             2
06/02/2010      China             0
06/03/2010      China            14
06/04/2010      China            23
06/05/2010      China            33

06/01/2010      Chile             3
06/02/2010      Chile             4
06/03/2010      Chile             0
06/04/2010      Chile             0
06/05/2010      Chile            19

你会怎么做？

注意： 我想看一些示例代码，开始： - ）

Answer 1

通常情况下，我会使用所有日期的计数器或数据透视表，然后根据该范围之间的日期加入。

类似于discussed here的技术。

Answer 2

这样的事情？

select d.Date, c.Country, sum(People) as PeopleNeeded 
from Dates d left join Requests r on d.Date between r.Start and r.End
group by d.Date, c.Country

其中日期包含适当的日期范围，如Cade Roux的答案

Answer 3

通常情况下，我建议使用一个包含日期顺序列表的静态日历表。但是，使用Cade Roux生成日历表的聪明方法，您可以使用以下内容：

;With Calendar As
    (
     Select Cast(Floor(Cast(@StartDate As float)) As datetime) As [Date]
     Union All
     Select DateAdd(d, 1, [Date])
     From Calendar
     Where DateAdd(d, 1, [Date]) < @EndDate
    )
Select C.[Date], R.Country, Sum(R.PeopleNeeded)
From Calendar As C
    Left Join Requests As R
        On C.[Date] Between R.[Start Date] And R.[End Date]
            And ( @Country Is Null Or R.Country = @Country )
Group By C.[Date], R.Country    
Option (MAXRECURSION 0);

现在，如果您希望在国家/地区进行过滤，以便返回的唯一天数是具有数据的给定国家/地区，那么您只需将左连接更改为内连接。

<强> ADDITION

从评论中，要求向所有国家/地区显示他们是否有请求。为此，您需要交叉连接到Countries表：

With Calendar As
    (
     Select Cast(Floor(Cast(@StartDate As float)) As datetime) As [Date]
     Union All
     Select DateAdd(d, 1, [Date])
     From Calendar
     Where DateAdd(d, 1, [Date]) < @EndDate
    )
Select C.[Date], C2.Country, Sum(R.PeopleNeeded)
From Calendar As C
    Cross Join Countries As C2
    Left Join Requests As R
        On C.[Date] Between R.[Start Date] And R.[End Date]
            And R.CountryId = C2.CountryId
Group By C.[Date], C2.Country    
Option (MAXRECURSION 0);

SQL QUERY在日期之间显示为特定日期+属于每个日期的数据！

3 个答案: