SQL 用于在 MS Access 中汇总子集的 25 个百分位值？

Question

当字段GICS Sector = "Energy":

时，获取GM字段的第25个百分位值

SELECT
  tblFirst250.[GICS Sector]
  , 0.75*(
    SELECT Max(GM) 
    FROM tblFirst250 
    WHERE tblFirst250.GM IN (
      SELECT TOP 25 PERCENT GM 
      FROM tblFirst250 
      WHERE tblFirst250.[GICS Sector ]= "Energy" AND GM Is Not Null ORDER BY GM)) + 0.25*(
        SELECT Min(GM) 
        FROM tblFirst250 
        WHERE tblFirst250.GM IN (
          SELECT TOP 75 PERCENT GM 
          FROM tblFirst250 
          WHERE tblFirst250.[GICS Sector] = "Energy" AND GM Is Not Null ORDER BY GM DESC)
  ) AS 25Percentile
FROM tblFirst250
WHERE tblFirst250.[GICS Sector] = "Energy"
GROUP BY tblFirst250.[GICS Sector];

...正确生成：

GICS 行业，25 个百分点
能量，-1.2

现在我正在尝试获取每个 GICS 部门的所有第 25 个百分位数。它看起来像这样：

GICS 行业，25 个百分点
能量，-1.2
工业，[一些值]
材料，[一些价值] ...等等

这是我 500 次尝试中的一次，但无法正常工作：

SELECT tbl.[GICS Sector], 0.75*(
SELECT Max(GM) 
FROM tbl 
WHERE tbl.GM IN (
SELECT TOP 25 PERCENT GM 
FROM tbl 
WHERE tbl.[GICS Sector] = tbl.[GICS Sector] AND GM Is Not Null ORDER BY GM)) + 0.25*(
SELECT Min(GM) 
FROM tbl 
WHERE tbl.GM IN (
SELECT TOP 75 PERCENT GM 
FROM tbl 
WHERE tbl.[GICS Sector] = tbl.[GICS Sector] AND GM Is Not Null ORDER BY GM DESC)
) AS 25Percentile
FROM tbl
WHERE tbl.[GICS Sector] = tbl.[GICS Sector]
GROUP BY tbl.[GICS Sector];

...以上结果对所有 GICS 部门产生了相同的值。我想为每个 GICS 部门提供不同的第 25 个百分位值。

Answer 1

我在另一个论坛上问了一个类似的问题，得到了这个答案： http://www.accessforums.net/queries/sql-aggregate-25-percentile-value-subsets-ms-53125.html#post280306

...这是正确的。感谢您对 Mark C 的所有帮助。希望这能为您节省一些时间。

这是它的核心，但不是全部。基本上是通过 GICS 扇区的循环：

Option Compare Database
Option Explicit
Function GetTop25Percent()
'MsgBox "I AM HERE"
    Call Top25PercentGroup
End Function
Sub Top25PercentGroup()
    Dim rawdata As String
    Dim desttbl As String
    Dim rs As DAO.Recordset
    Dim tmpName As String
    Dim tmpSQL As String

    rawdata = "tbl"
    desttbl = "tblTop25PCNT"

'MsgBox "I AM HERE"
    DoCmd.SetWarnings False
    DoCmd.OpenQuery "TruncateTblTop25PCNT"

    Set rs = CurrentDb.OpenRecordset("Unique GICS Sector")

'Check to see if the recordset actually contains rows
    If Not (rs.EOF And rs.BOF) Then
        rs.MoveFirst 'Unnecessary in this case, but still a good habit
        Do Until rs.EOF = True

            tmpName = rs("[GICS Sector]")

'Build top 25 % SQL For each GICS Sector
            tmpSQL = "INSERT INTO " & desttbl & " ( "
            tmpSQL = tmpSQL & "[GICS Sector], [GM] ) "
            tmpSQL = tmpSQL & "SELECT TOP 25 PERCENT [GICS Sector], [GM] "
            tmpSQL = tmpSQL & "FROM " & rawdata & " "
            tmpSQL = tmpSQL & "WHERE [GM] IS NOT NULL "
            tmpSQL = tmpSQL & "AND [GICS Sector] = """ & tmpName & """"

            DoCmd.RunSQL (tmpSQL)

'Move to the next record. Don't ever forget to do this.
            rs.MoveNext
        Loop
'    Else
'        MsgBox "There are no records in the recordset."
    End If

'        MsgBox "Finished looping through records."

    rs.Close            'Close the recordset
    Set rs = Nothing    'Clean up

    DoCmd.SetWarnings True
End Sub

SQL 用于在 MS Access 中汇总子集的 25 个百分位值？

SQL for Aggregate 25 percentile value for subsets in MS Access?

sql

ms-access

ms-access-2013