Question

我有一个用于存储用户记录的表

这包括列username，FromDate，ToDate，Status

我需要在1 Dec 2010和1 April 2011上找到活跃用户的数量（状态）。

换句话说，我们正在尝试确定1 Dec 2010和1 Apr 2011上有多少用户处于有效状态，以便我们可以比较已添加/丢失的用户数量。

如何做到这一点？

Answer 1

12月1日和4月1日均有效的用户：

with cte
as
(
    select UserName, FromDate, ToDate
    from MyTable
    where Status = 'Active' -- adjust to your status type
)
select distinct UserName
from cte
where 
    FromDate < '20101202' 
    and ToDate >= '20101201' and
    UserName in
    (
        select *
        from cte
        where FromDate < '20110402' and ToDate >= '20110401'
    )

要查看添加了哪些用户以及删除了哪些用户，您可以执行以下操作：

with cte
as
(
    select UserName, FromDate, ToDate
    from MyTable
    where Status = 'Active' -- adjust to your status type
)
select UserName, sum(WasActiveOnDecFirst) WasActiveOnDecFirst, sum(WasActiveOnAprFirst) WasActiveOnAprFirst
from
(
    select 
        isnull(du.UserName, au.UserName) UserName,
        case when du.UserName is null then 0 else 1 end WasActiveOnDecFirst,
        case when au.UserName is null then 0 else 1 end WasActiveOnAprFirst
    from
    (
        select distinct UserName
        from cte
        where FromDate < '20101202' and ToDate >= '20101201'
    ) du
        full join
    (
        select distinct UserName
        from cte
        where FromDate < '20110402' and ToDate >= '20110401'
    ) au
        on du.UserName = au.UserName
) tt
group by UserName
with rollup

结果如下：

UserName             WasActiveOnDecFirst WasActiveOnAprFirst
-------------------- ------------------- -------------------
user1                1                   1
user2                1                   1
user3                1                   1
user4                0                   1
NULL                 3                   4

最后一行是总用户数。

Answer 2

declare @FromDate date = '20101201'
declare @ToDate   date = '20110401'

select
  count(case when @FromDate between FromDate and ToDate then 1 end) as CountFromDate,
  count(case when @ToDate   between FromDate and ToDate then 1 end) as CountToDate
from YourTable
where FromDate <= @ToDate and
      ToDate >= @FromDate and
      Status = 1

Answer 3

编辑：请参阅Mikael Eriksson提供的答案。它看起来比我写的查询要好得多。

如果你只有两个比较日期，你可以这样做。屏幕截图＃ 1 显示针对示例数据的以下给定查询的输出。用户1，4，6和9在 2010-12-01 上有效。用户1，3，4，5，7和8在 2011-04-01 。因此，计数 4 和 6 。

DECLARE @Date1 DATETIME DECLARE @Date2 DATETIME SET @Date1 = '2010-12-01' SET @Date2 = '2011-04-01' SELECT @Date1 AS AsOnDate , COUNT(Username) AS ActiveCount FROM dbo.Users WHERE @Date1 BETWEEN FromDate AND ToDate UNION SELECT @Date2 AS AsOnDate , COUNT(Username) AS ActiveCount FROM dbo.Users WHERE @Date2 BETWEEN FromDate AND ToDate

希望有所帮助。

屏幕截图＃1：

在给定日期查找数据

3 个答案: