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khal

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custom aggregate function

I am trying to do the following:
in a select query I want to use Group by,and for one of the fields I want to be able to do a custom aggregate function (or call a function in a module) that concatenate the values of that field.
example:
Table1

F1   F2    F3
A    v1    a
B    v2    b
B    v2    c

I want the result of the query using group by and the custom function to be (group by F1,F2):

F1     F2     F3(after applying the function)
A      V1      a
B      V2      b,c        ......  concatenate fields

in brief, I am trying to use a similar function to the Access aggregate functions (like sum) where I can use it with group by. Any help of outlining the code to do this and what values to pass to the function is appreciated.


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krzycz
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Declare a public function (in any standard module):

Public Function funcConcatenate(txtFieldName As String, txtDomainName As String, txtCriteria As String, txtSeparator As String) As String
    Dim rs As DAO.Recordset
    Dim res As String
   
    res = ""
   
    Set rs = CurrentDb.OpenRecordset("SELECT " & txtFieldName & " FROM " & txtDomainName & " WHERE " & txtCriteria)
    If Not rs.BOF Then
        rs.MoveFirst
        While Not rs.EOF
            res = res & rs(txtFieldName) & txtSeparator
            rs.MoveNext
        Wend
        res = Left(res, Len(res) - Len(txtSeparator))
    End If
    rs.Close
   
    funcConcatenate = res
End Function



Usage:

SELECT F1, F2, funcConcatenate("F3", "TableName", "F1='" & F1 & "' AND F2='" & F2 & "'", ",") AS F3
FROM TableName
GROUP BY F1, F2;


HTH
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Avatar of khal
khal

ASKER

Thanks
it looks like this function will do it, but for some reason I am having an error when I am passing those variables from the query. It does not like the punctuation and it is giving error message
Compile error in query function funcConcatenate("F3", "Table1", "F1='" & F1 & "' AND F2='" & F2 & "'", ",") AS F3

do you see any problem with the punctuation?

Try to use semicolons ";" instead of commas "," to separate parameters.

What is the way you open your query?
Is it a saved query?
Avatar of khal

ASKER

semicolons did not work. I use a saved select query. What is the difference?

Avatar of khal

ASKER

This is the exact SQL for the query

SELECT Table1.f1, Table1.f2, funcConcatenate("F3", "Table1", "F1='" & F1 & "' AND F2='" & F2 & "'", ",") AS F3
FROM Table1
GROUP BY Table1.f1, Table1.f2;

 and this is the error message:

compile error in query expression 'funcConcatenate("F3", "Table1", "F1='" & F1 & "' AND F2='" & F2 & "'", ",")'.
ASKER CERTIFIED SOLUTION
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krzycz
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