Question

我正在寻找一种方法来获取一系列开始和结束日期的MEDIAN（很多和很多日期）。但是，它将特定于各种发票号码。＆＃34;请参阅下面的示例数据。

 invoice_no    invoice start date      invoice end date
 4006            11/14/2001               12/15/2004
 20071           11/29/2001               02/01/2003
 19893           11/30/2001               12/02/2001
 19894           11/30/2001               12/04/2001
 004             10/22/2002               10/31/2002
 004             12/02/2002               10/31/2002
 004             01/19/2002               10/31/2002
 004             05/10/2002               10/31/2002

查找开始日期和结束日期之间的中位数。

对于仅显示一次的发票，中位数只是该特定invoice_no的开始日期和结束日期之间的任何值。但是，很多情况下发票的方式都是004＆＃39;显示。它会在不同日期重复多次 - 但这里的概念仍然相同。需要找到两个日期之间的中位数，但仍需要根据该发票号显示。

尽可能过滤数据。我意识到我也可以做WHERE STATUS＆lt;＆gt; ＆＃39; REJECTED＆＃39;它还应该有助于保持很多不确定的日期。另外，我只想在几个月之间过滤，所以我也加入了BETWEEN DATETIME。

到目前为止

代码（但没有工作......如果有1个日期列，这种逻辑似乎有效，但现在我们正在处理两个日期，所以我不确定）：

 WITH
          tmp AS
    (
        SELECT invoice_no,
        invoice_start_date, invoice_end_date, check_date, status_code,
        cast(count(*) OVER (PARTITION BY invoice_no) as float) AS total,
        row_number() OVER (PARTITION BY invoice_no ORDER BY 
        invoice_start_date, invoice_end_date, check_date) AS rn

    FROM    INVOICE_HEADER INNER JOIN
   INVOICE_HEADER_CUSTOM ON INVOICE_HEADER.invoice_id 
    = INVOICE_HEADER_CUSTOM.invoice_id

    WHERE status_code <> 'REJECTED' AND 
    Check_Date BETWEEN CONVERT(DATETIME, '2014-12-01 00:00:00', 102) 
    AND CONVERT(DATETIME, '2014-12-31 00:00:00', 102)
)

    SELECT *
    FROM tmp
    WHERE (total / 2.0 - 1) < rn and rn < (total / 2.0 + 1)

Answer 1

好的...尝试像this page上的查询：

SELECT @Median = AVG(1.0 * val)
FROM 
(
  SELECT val, 
     c  = COUNT(*) OVER (),
     rn = ROW_NUMBER() OVER (ORDER BY val)
  FROM dbo.EvenRows
) AS x
WHERE rn IN ((c + 1)/2, (c + 2)/2);

Answer 2

如果您指的是设置的开始日期和结束日期，请将它们放在一列中：

WITH t AS (
       SELECT invoice_no, invoice_start_date, invoice_end_date, check_date, status_code,
       FROM INVOICE_HEADER INNER JOIN
            INVOICE_HEADER_CUSTOM
            ON INVOICE_HEADER.invoice_id = INVOICE_HEADER_CUSTOM.invoice_id
       WHERE status_code <> 'REJECTED' AND 
             Check_Date BETWEEN CONVERT(DATETIME, '2014-12-01 00:00:00', 102) AND
             CONVERT(DATETIME, '2014-12-31 00:00:00', 102)
     ), 
     t2 as (
      select d, row_number() over (order by d) as seqnum,
             count(*) over () as cnt
      from (select invoice_start_date as d from t
            union all
            select invoice_end_date as d from t
           ) t
     )
select dateadd(day, datediff(hour, min(d), max(d)) / 2.0, min(d))
from t2
where 2 * seqnum in (cnt, cnt + 1, cnt + 2);

在两个日期SQL Server 2008之间查找中位数

2 个答案: