Interesting issue with ADODB connection: UDF using ADODB works fine when called from VBA code, but it returns error when called from EXCEL cell

Question

I have been using ADODB connection from within Excel in order to connect to MySql databases and retrieve values.

The essence of my code is as follows:

Public Function ODPH(B0 As Range, sqlstr As Variant)


Dim oconn As ADODB.Connection
Dim rs As ADODB.Recordset


On Error GoTo error_handler



'Connect to MySql. Assign default values if connection string is missing!

ipDriver = "{MySQL ODBC 5.2 Unicode Driver}"
ipType = "MySql"
If IsEmpty(ipHost) Then ipHost = "HHHH"
If IsEmpty(ipUser) Then ipUser = "UUUU"
If IsEmpty(ipdbName) Then ipdbName = "DDDD"
If IsEmpty(ipPasswd) Then ipPasswd = "PPPP"

strConn = "DRIVER=" & ipDriver & ";" & _
"SERVER=" & ipHost & ";" & _
"DATABASE=" & ipdbName & ";" & _
"USER=" & ipUser & ";" & _
"PASSWORD=" & ipPasswd & ";" & _
"Option=" & ipOption

Set oconn = New ADODB.Connection
oconn.Open strConn

oconn.CursorLocation = adUseClient
'oconn.CursorLocation = adUseServer

Set rs = New ADODB.Recordset
' rs.Open sqlstr, oconn, adLockOptimistic
' rs.Open sqlstr, oconn, adLockReadOnly
rs.Open sqlstr, oconn, adOpenStatic, adLockOptimistic
rs.Open sqlstr, oconn

If rs.EOF Then
'MsgBox "No records returned!"
    ODPH = "#No record at db"
    Exit Function

    Else
    'rs.MoveLast
    rCount = rs.RecordCount
    Select Case rCount
        Case Is > 1
            ODPH = "#many records from db"
            Exit Function

        Case Else

            Select Case rs.Fields.Count
                Case Is > 1
                ODPH = "#many columns from db"
                Exit Function

                Case Else
                Select Case IsNull(rs.Fields(0).Value)

                    Case Is = True
                        ODPH = "#null at db"
                        Exit Function

                    Case Else
                        aux = rs(0).Value
                        Select Case IsNumeric(aux)
                            Case Is = True
                            ODPH = CDbl(aux)
                            Exit Function

                            Case Else
                            ODPH = aux
                            Exit Function
                        End Select

                End Select
        End Select

    End Select

End If

'Error handler
error_handler:
    ODPH = Err.Description
    Exit Function

End Function

My issue is that:

• This code works well when it is called from another VBA sub or function.
• But this function returns the following error when it is called from one excel cell as a UDF function:

"Arguments are of the wrong type, are out of acceptable range, or are in conflict with one another." (Error number 3001)

I really could not understand why one set of code returns no error when it is called by VBA editor whereas it returns this error when it is called from one excel cell as a user-defined function!

Any help is appreciated.

Best regards,

Answer 1

By definition, UDF needs to return something and you are missing the return type like:

Public Function ODPH(B0 As Range, sqlstr As Variant) As Variant

Calling it from another macro works, because VBA (or almost all programming languages) don't really care if you have a receiving variable of function.