计算 2 个日期列

Question

所以我有 2 个日期列，开始和结束。我要完成的是每天的库存，这将追溯到 2020 年初，因此我拥有这些字段：

开始日期、当天新增的数量、当天关闭的数量以及前几天的现有打开数量。我派生的基本数据结构是开始日期、结束日期、请求类型（如果开始日期 = 报告日期且结束日期为空，则“新添加”，如果结束日期不为空，则“工作已结束”，如果开始日期为小于报告日期然后“现有打开”。问题是这些取决于报告日期和打开/关闭日期之间的相关性。我需要能够按日期分组并给出每天的计数。我试过这些2 个解决方案，并没有像我希望的那样工作，因为它们与我的情况略有不同。（Count Function on Multiple Columns by Date (SQL Server) 和Get count on two different date columns and group by date）。当我总结时，我需要根据当前日期每天进行计数库存和前一天的现有物品。

我的基本数据结构是这样的，是假数据：

+----+------------+-----------+---+
| ID | StartDate  |  EndDate  |   |
+----+------------+-----------+---+
|  1 | 1/1/2020   |  NULL     |   |
|  2 | 12/1/2019  | 1/1/2020  |   |
|  3 | 1/1/2020   |  1/3/2020 |   |
|  4 | 12/17/2019 | 1/2/2020  |   |
+----+------------+-----------+---+

预期结果：

+-------------+---------+-----------------+-----------+--+--+------+
| Report Date | NewAdds |    ExistingOpen |    Closed |  |  |      |
+-------------+---------+-----------------+-----------+--+--+------+
| 1/1/2020    |       2 |          1       |         1 |  |  |    |
| 1/2/2020    |       0 |          1      |         1 |  |  |     |
| 1/3/2020    |       0 |          1      |         1 |  |  |     |
+-------------+---------+-----------------+-----------+--+--+------+

Answer 1

set @report_start = '20200101';
set @report_end = '20200103';

select
    d.dt,
    count(case when t.start_dt = d.dt then 1 end) as Adds,
    count(case when d.dt > t.start_dt and d.dt < t.end_dt as Existing,
    count(case when t.end_dt = d.dt then 1 end) as Closed
from T t inner join Dates d on d.dt <= coalesce(t.end_dt, @report_end)
where d.dt between @report_start and @report_end
group by d.dt;

创建一个日期表并加入它。那时计数相当容易。

这是一个坏主意，因为您需要计算所有日期。我也不知道空结束日期是什么意思。如果这是我在手机上输入时的草率，请致歉。

Answer 2

这是修复处理任何报告日期的逻辑的解决方案的开始：

If Start_date = report_date and (end_date is null or  end_date > report date) then 'New Add'

if end_date is not null and end_date <= report_date then 'Work Closed'

if Start_Date < report_date  and (end_date is null or end_date > report_date then 'Existing Open'

您需要一个可以为您提供三个值之一的 case 表达式。

一旦您让它适用于单个报告日期，您就可以使用此解决方案生成一系列报告日期并将其加入您的表格：Generate Dates between date ranges

Answer 3

要实施我的解决方案，请添加一个用于管理日历的表格

你必须做几个步骤来解决这个问题：

1. 确定每个日历间隔打开哪些任务 (NewAddTask)
2. 按时间间隔计算打开的任务总数 (TotalNewAddTask)
3. 确定每个日历间隔的关闭任务 (ClosedTask)
4. 按时间间隔计算关闭任务总数(TotalClosedTask)
5. 计算间隔组合的时间表 (ExistingOpenCalendar)
6. 确定每个日历间隔的现有打开的任务 (ExistingOpenDetail)
7. 按时间间隔计算现有打开任务总数(TotalExistingOpenTask)

8. 我终于把所有的总数和日历结合起来了

   with NewAddTask as
   (
           SELECT IdCalendar,IdTask
           FROM
           Calendar CROSS JOIN Task 
           where StarDate  between FirstDate and LastDate
   ),
   TotalNewAddTask as
   (
           select IdCalendar,count(IdTask) as Total
           from NewAddTask 
           group by IdCalendar
   ),
   ClosedTask as
   (
           SELECT IdCalendar,IdTask
           FROM
           Calendar CROSS JOIN Task 
           where isnull(CloseDate,'2020-12-31') between FirstDate and LastDate
   ),
   TotalClosedTask as
   (
           select IdCalendar,count(IdTask) as Total
           from ClosedTask 
           group by IdCalendar
   ),
   ExistingOpenCalendar as 
   (
           SELECT 
           Calendarend.IdCalendar ,
           CalendarStart.FirstDate,
           Calendarend.LastDate
           FROM
           Calendar as CalendarStart CROSS JOIN Calendar as Calendarend 
           where 
           CalendarStart.FirstDate<Calendarend.LastDate
   )
   , ExistingOpenDetail as
   (
           select ExistingOpenCalendar.IdCalendar,Task.IdTask 
           from ExistingOpenCalendar CROSS JOIN Task 
           where StarDate  between FirstDate and LastDate
           and not (isnull(CloseDate,'2020-12-31') between FirstDate and LastDate)
           and (CloseDate is null  or (CloseDate < LastDate))
   )
   ,TotalExistingOpenTask  as
   (
           select IdCalendar,count(IdTask) as Total 
           from ExistingOpenDetail
           group by IdCalendar
   )
   select 
   Calendar.IdCalendar,Calendar.FirstDate ,
   isnull(TotalNewAddTask.Total,0)as NewAddTask,
   isnull(TotalClosedTask.Total,0)as ClosedTask,
   isnull(TotalExistingOpenTask.Total,0)as ExistingOpen
   from Calendar 
   left join TotalNewAddTask on Calendar.IdCalendar=TotalNewAddTask.IdCalendar
   left join TotalClosedTask on Calendar.IdCalendar=TotalClosedTask.IdCalendar
   left join TotalExistingOpenTask on Calendar.IdCalendar=TotalExistingOpenTask.IdCalendar
   

此查询满足条件

in this example you can find example