Access 97 Report on Difference Between Fields

[shankbanta]

I am having a probllem creating a report that shows the calculated difference between two numbers. I am running this report from a query that allows a date range for a monthly report.

Ex. Table: Machine, Unit, Date, Impression (There are several different machines(21, 15, 22, etc), each machine has up to 6 units, each unit has a counter).

In my report I group by machine then unit. I need to get the difference between the counters.

Ex.

Machine Unit Date Impresion (Header)
21 1 4/10/03 1234 (Details)
4/15/03 1566
21 3 4/03/03 6898
4/15/03 9666
22 5 3/1/03 5555
3/2/03 6666


I need show the difference between the impresion counts. All information is in one table with no defined primary key.

All suggestions are appreciated.

 

[fneily]

What you might do is create one record out of two (based on machine and unit). Then just do a direct substraction. To concatenate the records, change the following to suit your needs:

I made a table with two fields - partno, desc. Desc can span more than one record, eg.
partno desc
abcd this is one desc
abcd this is two desc
xyz another desc
xyz more desc
etc. etc.

I want to concatenate the desc's into one field.

create a query that looks like this:
SELECT [partno], fConcatFld("parttable","partno","desc","string",[partno]) AS descs
FROM parttable
GROUP BY [partno];

Do ALT+F11, insert a new module and put the following code for the fConcatFld function:

Function fConcatFld(stTable As String, _
stForFld As String, _
stFldToConcat As String, _
stForFldType As String, _
vForFldVal As Variant) _
As String

'Usage Examples:
' ?fConcatFld(("Customers","ContactTitle","CustomerID", _
' "string","Owner&quot
'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 DAO.Recordset
Dim lovConcat As Variant, loCriteria As String
Dim loSQL As String

On Error GoTo Err_fConcatFld

lovConcat = Null
Set lodb = CurrentDb


loSQL = "SELECT [" & stFldToConcat & "] FROM [" & stTable & "] WHERE [" & stForFld & "] = '" & vForFldVal & "' ;" 'place this line on one line in the VBA window.

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) & &quot; &quot;
.MoveNext
Loop
Else
GoTo Exit_fConcatFld
End If
End With

'Just Trim the trailing ;
fConcatFld = Left(lovConcat, Len(lovConcat) - 1)


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

Err_fConcatFld:
MsgBox &quot;Error#: &quot; & Err.Number & vbCrLf & Err.description
Resume Exit_fConcatFld
End Function

Run the query, which calls the function. Besure in your VBA window, click on Tools , the References and make sure the DAO library is referenced first.

Then you can take this answer through another query or report and do the subtraction.

Neil