Concatenate multiple rows in one field in Access? [duplicate]

Answer 1

You should not create a reference table that concatenates records. That is denormalizing the database.

You can try a crosstab query like below, but I have not tested it. You can read here for more information.

TRANSFORM First([Product Types]) AS Product
SELECT [Order Number], First([Product Types])
FROM CurrentTable
GROUP [Order Number]

Answer 2

Allen Browne provides a function which you may find useful for this: Concatenate values from related records. Save that function's code in a standard module.

SELECT DISTINCT
    [Order Number],
    ConcatRelated("[Product Types]",
        "YourTable",
        "[Order Number] = " & [Order Number],
        "[Product Types]",
        "/"
        ) AS All_Product_Types
FROM YourTable;

I tested that query in Access 2007 with your sample data saved in a table named "YourTable". It returned the results you asked for. However, this only works from within an Access session. If you wanted to run this query from outside Access (like from ASP), user-defined functions are not available, so you would get an error about ConcatRelated() not recognized.

So you can use a query to retrieve the concatenated values whenever you need them. However if you store those concatenated values, they can quickly be out of sync with changes to the base table's data.

Answer 3

If I understand the question, you're asking how to get the order numbers of just those orders who have TV, AND phone, AND internet. If you're just interested in those order numbers you could run a query like:

SELECT Distinct Table1.OrderNumber
FROM (Select OrderNumber from Table1 where [product types]= "Internet")  AS i
    INNER JOIN ((Select OrderNumber from Table1 where [product types]="Phone")  AS p 
    INNER JOIN ((Select OrderNumber from Table1 Where [product types]= "TV")  AS tv 
    INNER JOIN Table1 ON tv.OrderNumber = Table1.OrderNumber) ON p.OrderNumber = Table1.OrderNumber) ON i.OrderNumber = Table1.OrderNumber;

Answer 4

As was pointed out by onedaywhen in an early post on SO, this is easier with ADO: Sample query:

   SELECT [Order Number], 
          ConcatADO("SELECT [Product Types] FROM Orders
                     WHERE [Order Number]=" & [Order Number],", "," : ") AS Cat
   FROM Orders
   GROUP BY [Order Number], 2;

Function using ADO

Function ConcatADO(strSQL As String, strColDelim, _
   strRowDelim, ParamArray NameList() As Variant)

   Dim rs As New ADODB.Recordset
   Dim strList As String

   On Error GoTo Proc_Err

       If strSQL <> "" Then
           rs.Open strSQL, CurrentProject.Connection
           strList = rs.GetString(, , strColDelim, strRowDelim)
           strList = Mid(strList, 1, Len(strList) - Len(strRowDelim))
       Else
           strList = Join(NameList, strColDelim)
       End If

       ConcatADO = strList

   Exit Function

   Proc_Err:
       ConcatADO = "***" & UCase(Err.Description)
End Function