Find an item by non-key column in dataset

Hi,
This expression worked to some extent. Thanks a lot for it
However, there is some problem.
I have another column called "OLDITEM" in the same table
It is a text field. In fact all fields are text fields because itemNo and OLDITEM and UPCCode can include letters.
My modified expression of a function to define itemNo by either upc or olditem looks like that:

*******************
Public Function itemNoBy(ByVal byWhat As String, ByVal num As String) As String
        Dim itemNo As String
        Dim dr As DataRow()
       
        'parameters passed to this function are either "upc" or "old"
        Select Case byWhat
            Case "upc"
                dr = myRef.dsJB.Itemweb.Select("UPCCODE = " & num)
            Case "old"
                dr = myRef.dsJB.Itemweb.Select("OLDITEM = " & num)
        End Select

        If dr.Length > 0 Then
            itemNo = dr(0)("itemNo").ToString
        Else
            itemNo = "Not Found"
        End If

        Return itemNo
End Function

***********************

Now, when i pass upc - everything works out perfect, however, when i pass old - i get this error. Why would i get it? All fields have absolutely the same properties, they are all text fields and in my dataset they are all String fields.

An unhandled exception of type 'System.Data.EvaluateException' occurred in system.data.dll

Additional information: Cannot perform '=' operation on System.String and System.Int32.

Oh, I think I see what's happening.  Suppose num is 555.

When you construct the statement
"UPCCODE = " & num

it is constructed as
"UPCCODE = 555"

which is a numeric search, not a string search.  Try changing those statements to
"UPCCODE = '" & num & "'"

It's tough to see, but there are single quotes in there.