access合并多行列数据到一行，类似于mysql的group_concact()函数

Concatenate fields in same table
Author(s)
Dev Ashish

(Q) I need to concatenate a field in the format "Value1; Value2; Value3" etc. for each unique value of another field in the same table. How can I do this?
(A) Using the fConcatFld function, in the Northwind database, the following query should return a concatenated list of all CustomerIDs if you group by ContactTitle.
使用方式：
SELECT ContactTitle, fConcatFld("Customers","ContactTitle","CustomerID","string",[ContactTitle]) AS Customers FROM Customers GROUP BY ContactTitle;

参数说明：
fConcatFld参数说明

stTable As String 表名称
_stForFld As String, 查询的条件字段名称
_stFldToConcat As String, 合并的字段名称
_ stForFldType As String, 合并字段的类型
_vForFldVal As Variant 合并字段的查询条件
'************ Code Start **********
'This code was originally written by Dev Ashish
'It is not to be altered or distributed,
'except as part of an application.
'You are free to use it in any application,
'provided the copyright notice is left unchanged.
'
'Code Courtesy of
'Dev Ashish
'

Function fConcatFld(stTable As String, _
                    stForFld As String, _
                    stFldToConcat As String, _
                    stForFldType As String, _
                    vForFldVal As Variant) _
                    As String
'Returns mutiple field values for each unique value
'of another field in a single table
'in a semi-colon separated format.
'
'Usage Examples:
'   ?fConcatFld(("Customers","ContactTitle","CustomerID", _
'                "string","Owner")
'Where Customers     = The parent Table
'       ContactTitle = The field whose values to use for lookups
'       CustomerID    = Field name to concatenate
'       string        = DataType of ContactTitle field
'       Owner         = Value on which to return concatenated CustomerID
'

Dim lodb As Database, lors As Recordset
Dim lovConcat As Variant, loCriteria As String
Dim loSQL As String
Const cQ = """"

    On Error GoTo Err_fConcatFld

    lovConcat = Null
    Set lodb = CurrentDb

    loSQL = "SELECT [" & stFldToConcat & "] FROM ["
    loSQL = loSQL & stTable & "] WHERE "

    Select Case stForFldType
        Case "String":
            loSQL = loSQL & "[" & stForFld & "] =" & cQ & vForFldVal & cQ
        Case "Long", "Integer", "Double":    'AutoNumber is Type Long

            loSQL = loSQL & "[" & stForFld & "] = " & vForFldVal
        Case Else
            GoTo Err_fConcatFld
    End Select

    Set lors = lodb.OpenRecordset(loSQL, dbOpenSnapshot)

    'Are we sure that duplicates exist in stFldToConcat

    With lors
        If .RecordCount <> 0 Then
            'start concatenating records

            Do While Not .EOF
                lovConcat = lovConcat & lors(stFldToConcat) & "; "
                .MoveNext
            Loop
        Else
            GoTo Exit_fConcatFld
        End If
    End With

    'That's it... you should have a concatenated string now
    'Just Trim the trailing ;

fConcatFld = Left(lovConcat, Len(lovConcat) - 2)

Exit_fConcatFld:
Set lors = Nothing: Set lodb = Nothing
Exit Function

Err_fConcatFld:
MsgBox "Error#: " & Err.Number & vbCrLf & Err.Description
Resume Exit_fConcatFld
End Function
'************ Code End **********

作者“无名程序员”