Question

我有一组数据，包括filenbr，开放日期和结束日期。

我需要生成一个类似于下面的摘要表，我需要计算每天有多少文件，但我需要将那些大于20的文件组合在一起。我知道如何获得约会，我磕磕绊绊的是如何获得20+和％列

1 day - 30 files - 30%
3 days - 25 files - 25%
10 days - 5 files - 5%
13 days - 20 files - 20%
>= 20 days - 20 files - 20%

Answer 1

假设您有一个名为dayFile的表，其中包含以下列

Table DayFile

days - files
1    - 10
1    - 5
1    - 15
3    - 20
3    - 5
10   - 5
13   - 20
20   - 5
22   - 5
28   - 10

然后你可以做以下

SELECT
    SummaryTable.Day,
    SUM(SummaryTable.Files) as SumFiles,
    Sum(SummaryTable.Files) / SummaryTable.TotalFiles
  FROM 
    (SELECT 
      CASE WHEN (days >= 20) THEN
        20
      ELSE DF.days END as Day
      files,
      (SELECT Count(*) FROM DayFile DFCount) as TotalFiles
    FROM DayFile DF) SummaryTable
Group By SummaryTable.Day

<强>编辑：

SELECT
    SummaryTable.Day,
    SUM(SummaryTable.Files) as SumFiles,
    Sum(SummaryTable.Files) / (SELECT Count(*) FROM DayFile DFCount)
FROM 
    (SELECT 
      CASE WHEN (days >= 20) THEN
        20
      ELSE DF.days END as Day
      files
    FROM DayFile DF) SummaryTable
Group By SummaryTable.Day

Answer 2

您不清楚如何确定范围（例如“3天平均<3天，<= 3天，= 3天，> 3天或> = 3天？”。如果您正在使用SQL Server 2005及更高版本，您可以获得如下结果：

With PeriodLength As
    (
    Select DateDiff(d, OpenDate, CloseDate) As DiffDays
    From Table
    )
    , Ranges As 
    (
    Select Case
            When DiffDays < 3 Then 'Less than 3 Days'
            When DiffDays >= 3 And DiffDays < 10 Then 'Less than 10 Days'
            When DiffDays >= 10 And DiffDays < 13 Then 'Less than 13 Days'
            When DiffDays >= 13 And DiffDays < 20 Then 'Less than 20 Days'
            When DiffDays >= 20 Then 'Greater than 20 days'
            End As Range
    From PeriodLength   
    )
Select Range
    , Count(*) As FileCount
    , Count(*) * 100.000 / (Select Count(*) From Ranges) As Percentage
From Ranges 
Group By Range

T-SQL问题 - 计数和平均值

2 个答案: