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custom aggregate function

Posted on 2001-07-06
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Last Modified: 2007-12-19
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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Question by:khal
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6 Comments
 
LVL 4

Expert Comment

by:krzycz
ID: 6261056

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
Need help? - Just @skme!
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Author Comment

by:khal
ID: 6261129
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?

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LVL 4

Expert Comment

by:krzycz
ID: 6261641
Try to use semicolons ";" instead of commas "," to separate parameters.

What is the way you open your query?
Is it a saved query?
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Author Comment

by:khal
ID: 6261707
semicolons did not work. I use a saved select query. What is the difference?

0
 

Author Comment

by:khal
ID: 6261712
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 & "'", ",")'.
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LVL 4

Accepted Solution

by:
krzycz earned 100 total points
ID: 6261738
I have no idea.
I've just checked this function with one of my tables and it works fine.

Are you sure the function works? Did you try to compile all the modules?

Try to use this function in another simple query. i.e. just:

SELECT funcConcatenate("F3", "Table1", "F1='" & F1 & "' AND F2='" & F2 & "'",
",") AS F3
FROM Table1;

Maybe it will be easier to find an error.

Finally, you can send me a copy of your database (you can delete all the non-required objects). Just keep the table, the query and the module with the function. Then compress it and send me as a ZIP archive.
I'll try to help you.

krzycz@amg.gda.pl
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