Question

我需要计算日期差异的平均值，不包括列中各行的周末。该查询给了我错误的结果。但是，当我自己计算时，我会得到不同的结果。查询类似于 -

select zone, avg(datediff(dd,startdate,enddate)-datediff((ww,startdate,enddate)*2)) from table where startdate >'1/1/2013' group by zone

我没有得到正确的结果。请指导我。

Answer 1

试试这段代码：

    select zone , avg(NumOfDays) from
          (select zone, (datediff(dd,startdate,enddate)-datediff((ww,startdate,enddate)*2)) as         NumOfDays from table where startdate >'1/1/2013')
    group by zone

Answer 2

我不知道你的数据是什么样的，你究竟挑战的是什么，但我认为你的问题是“排除周末”？也许这对你有帮助吗？

首先创建一个函数，计算您的句点之间的每个周末日，以便稍后过滤它：

CREATE FUNCTION fnc_GetWeekendDays(@dFrom DATETIME, @dTo   DATETIME)
RETURNS INT AS
BEGIN
   Declare @weekendDays int
   Set @weekendDays = 0

   While @dFrom <= @dTo 
   Begin
      If ((datepart(dw, @dFrom) = 1) OR (datepart(dw, @dFrom) = 7))    
                  Set @weekendDays = @weekendDays + 1
                  Set @dFrom = DateAdd(d, 1, @dFrom)

    End
   Return (@weekendDays)
END

在此之后，写下您的查询：

Select
zone,
avg(cast((datediff(SECOND,StartTime,EndTime) - dbo.fnc_GetWeekendDays(StartTime, EndTime)*86400) as float))
from
    (
        Select zone,
        CASE 
            WHEN (datepart(dw, startdate) = 1) THEN DATEADD(Day, DATEDIFF(Day, 0, startdate), 1) 
            WHEN (datepart(dw, startdate) = 7) THEN DATEADD(Day, DATEDIFF(Day, 0, startdate), 2) 
            ELSE startdate END as StartTime, 
        CASE 
            WHEN (datepart(dw, enddate) = 1) THEN DATEADD(Day, DATEDIFF(Day, 0, enddate), -2) 
            WHEN (datepart(dw, enddate) = 7) THEN DATEADD(Day, DATEDIFF(Day, 0, enddate), -1) 
            ELSE enddateEND as EndTime
        from  table
    ) subquery
where StartTime < EndTime and startdate >'2013-01-01 00:00:00.000'
Group by zone

如果你想要另一种格式，你将得到平均时间（以秒为单位）......

计算sql server中列的日期差异的平均值

2 个答案: