Question

我的项目包含一个MS Acces 2003数据库，数据库中的表包含一个名为学生名称的列。单列包含n个学生名称。例如。约翰，吉姆，约翰尼，汤姆等。他们是动态添加的。现在我想要的是，我想要列中所有名称的完整列表。喜欢例如。如果列是

Student_name

John, Jim, Johny, Tom, Jack

我希望输出为：

Student_name

John
Jim
Johny
Tom
Jack

查询必须支持MS Access。因为我正在获取html文件中的数据，我已将该html文件附加到MS Aacess数据库

Answer 1

很抱歉，但MS Access不提供以递归模式运行查询的功能CTE。可以使用VBA宏继续学生收集，将逗号分隔值拆分为一组记录;）

比方说，你有表学生的字段：

ID（数字 - 整数），
学生（字符串 - 字符）

示例数据：

Id Students
1   John, Jim, Johny, Tom, Jack
2   Paula, Robert, Tim, Dorothy
5   Frank, Ramona, Giorgio, Teresa, Barbara
19  Isabell, Eve, Ewelina, Tadit

您需要创建另一个表来存储宏的结果。

CREATE TABLE CTE1
(
    ID INT,
    OrigValue CHAR(255),
    SingleValue CHAR(255),
    Remainder CHAR(255)
);

要添加宏，请执行以下步骤：

转到Visual Basic代码窗格
插入新模块
复制下面的代码并将其粘贴到以前添加的模块
通过在其正文中单击
运行代码（F5）

Option Compare Database
Option Explicit

'need reference to Microsoft ActiveX Data Object 2.8 Library

Sub ModifyMyData()
Dim sSQL As String
Dim rst As ADODB.Recordset
Dim vArray As Variant
Dim i As Integer

'clear CTE table
sSQL = "DELETE * FROM CTE;"
CurrentDb.Execute sSQL

'initial query
sSQL = "INSERT INTO CTE (ID, OrigValue, SingleValue, Remainder)" & vbCr & _
    "SELECT ID, Students AS OrigValue, TRIM(LEFT(Students, InStr(1,Students,',')-1)) AS SingleValue, " & _
                "TRIM(RIGHT(Students,LEN(Students)-InStr(1,Students,','))) AS Remainder" & vbCr & _
    "FROM Student;"
CurrentDb.Execute sSQL

sSQL = "SELECT ID, OrigValue, SingleValue, Remainder" & vbCr & _
    "FROM CTE"
Set rst = New ADODB.Recordset
rst.Open sSQL, CurrentProject.Connection, adOpenStatic
With rst
    'fill rst object
    .MoveLast
    .MoveFirst
    'proccess through the
    Do While Not rst.EOF
        'Split Remainder into array
        vArray = Split(.Fields("Remainder"), ",")
        'add every single value
        For i = LBound(vArray) To UBound(vArray)
            sSQL = "INSERT INTO CTE (ID, OrigValue, SingleValue, Remainder)" & vbCr & _
                "VALUES(" & .Fields("ID") & ", '" & .Fields("OrigValue") & "','" & vArray(i) & "','" & GetRemainder(vArray, i + 1) & "');"
            CurrentDb.Execute sSQL
        Next
        .MoveNext
    Loop
    .Close
End With

Set rst = Nothing

MsgBox "Ready!"

DoCmd.OpenTable "CTE"

End Sub


Function GetRemainder(vList As Variant, startpos As Integer) As String
Dim i As Integer, sTmp As String
For i = startpos To UBound(vList)
    sTmp = sTmp & vList(i) & ","
Next

If Len(sTmp) > 0 Then sTmp = Left(sTmp, Len(sTmp) - 1)
GetRemainder = sTmp

End Function

MS Access查询以分隔逗号

1 个答案: