このクエリを作成して値を結合するにはどうすればよいですか？
I have a table with the following structure and values:
EventID PersonName
----------- ------------
1 John
1 Peter
1 Sylvia
2 John
2 Sylvia
3 Peter
3 June
I'd like to run a query and get results in the following format:
EventID PersonNames
-------- ---------------
1 John, Peter, Sylvia
2 John, Sylvia
3 Peter, June
これを達成するクエリがありますか？
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.
SELECT ContactTitle, fConcatFld("Customers","ContactTitle","CustomerID","string",[ContactTitle]) AS CustomersFROM CustomersGROUP BY ContactTitle;
'************ 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 **********
コードモジュールにfConcatFld（）関数をコピーして貼り付けます。コードの 以下VBAラインを変更：
lovConcat = lovConcat &のLOR（stFldToConcat）& ";"
に：
lovConcat = lovConcat &のLOR（stFldToConcat）& ""
...それを保存し、コードをコンパイルします。
次に、新しいクエリを作成し、SQLビューでクエリを開き、SQLビューペインに 次のSQLステートメントを貼り付けます。
SELECT EventID, fConcatFld("MyTable","EventID","PersonName","Long", EventID)
AS PersonNames
FROM MyTable
GROUP BY EventID;
...とあなたの名前で「MyTableという」を置き換えます表。"EventID" データ型がLongでない場合は、SQL文の でもフィールドが使用しているデータ型に置き換える必要があります。
クエリを保存して実行します。 Voila！コンマ区切りリスト。
source_fruitの値はどこで取得できますか？ – Stefan
私はここに含まれていない宣言を作成しました： set source_fruit = rstsource.Fields（ "fruits_list_type"） – Joy
私はあなたの結果が最初の値を2回（result = source_table）得ると思います。あなたが間違った出力を示すことができれば、問題を見つけやすくなります。 – Stefan