如何在 SQL 中获取 3 天的记录分组日期？

Question

每 5 天对记录进行分组和显示变得越来越困难。

这是我的数据：

FLIGHT_DATE LANDINGS    PILOTID COPILOTNAME MONT    DPT

11/16/2013  1   A   B   11  5.5
11/17/2013  1   A   B   11  13
11/19/2013  1   A   B   11  12.55
11/19/2013  1   A   B   11  4
11/21/2013  1   A   B   12  6
11/24/2013  1   A   B   12  6.03
11/25/2013  1   A   B   11  5.5
11/26/2013  1   A   B   11  13
11/26/2013  1   A   B   11  12.55
11/30/2013  1   A   B   11  4
12/1/2013   1   A   B   12  6
12/2/2013   1   A   B   12  6.03        

我想显示如下：

Week Start  Week End    DPT         
11/17/2013  11/21/2013  35.55           
11/22/2013  11/26/2013  37.08           
11/27/2013  12/1/2013   6           
12/2/2013   12/6/2013   6.03

Answer 1

这是我提出的解决方案：

DECLARE @MinDate AS DATETIME = (SELECT MIN(flight_date) FROM flights);

WITH cte
AS
(
    SELECT
        flight_date, DATEDIFF(DAY, @MinDate, flight_date) AS NoDays,
        DATEDIFF(DAY, @MinDate, flight_date)/5 AS NoGroup,
        DPT
    FROM flights
)
SELECT  
    DATEADD(DAY, NoGroup*5, @MinDate) AS [Week Start],
    DATEADD(DAY, NoGroup*5+4, @MinDate) AS [Weed End],  
    SUM(DPT)
FROM cte
GROUP BY NoGroup;

这个想法是形成 5 天的组，然后将记录与基于除法的特定组关联 5。NoDays 表示从 MinDate 到 Flight_Date 所用的天数。

Answer 2

您可以使用此查询。您需要指定要计算的开始日期和每个期间的天数（在您的情况下似乎是 5），但请根据需要调整这些数字。

declare @startdate date = '20131117'
declare @interval int = 5

select dateadd(dd, @interval * (o.number - 1), @startdate) WeekStart, 
    dateadd(dd, @interval * o.number - 1, @startdate) WeekEnd,
    sum(d.DPT) DPT
from yourtable d
inner join
    (select ROW_NUMBER() over (order by object_id) as number from sys.all_objects) as o
on d.FLIGHT_DATE >= dateadd(dd, @interval * (o.number - 1), @startdate)
and d.FLIGHT_DATE < dateadd(dd, @interval * o.number, @startdate)
group by o.number
order by dateadd(dd, @interval * (o.number - 1), @startdate)