UDF function in Excel running ACE SQL query, JOIN two tables does not work

Question

I am trying to figure out what wrong may be with a function in Excel that tries to join two tables. I presume the error is somewhere in SQL string.

The function works well without a join, returning correctly a table to an array - range of cells. ie when strSQL is only "SELECT * FROM [" & currAddress & "] "

It does not work when the string contains a join, ie strSQL = "SELECT * FROM [" & currAddress & "] " & _ "LEFT JOIN [" & currAddress2 & "] ON [Indeks].[" & currAddress & "] = [Indeks2].[" & currAddress2 & "];"

Here is my code, thank you for help:

    Function SQL(dataRange As Range, dataRange2 As Range) As Variant
    Application.Volatile

    Dim cn As ADODB.Connection
    Dim rs As ADODB.Recordset
    Dim currAddress, currAddress2 As String
    Dim varHdr, varDat, contentOut As Variant
    Dim nc, nr, i, j As Long

    SQL = Null

    currAddress = ActiveSheet.Name & "$" & dataRange.Address(False, False)
    Debug.Print currAddress

    currAddress2 = ActiveSheet.Name & "$" & dataRange2.Address(False, False)
    Debug.Print currAddress2


    strFile = ThisWorkbook.FullName
    strCon = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & strFile _
    & ";Extended Properties=""Excel 12.0;HDR=Yes;IMEX=0"";"

    Set cn = CreateObject("ADODB.Connection")
    Set rs = CreateObject("ADODB.Recordset")

    rs.CursorLocation = adUseClient ' required to return the number of rows correctly
    cn.Open strCon



        strSQL = "SELECT * FROM [" & currAddress & "] " & _
             "LEFT JOIN  [" & currAddress2 & "] ON [Indeks].[" & currAddress & "] = [Indeks2].[" & currAddress2 & "];"


   Debug.Print strSQL

    rs.Open strSQL, cn

    'Check if recordset is empty
    If rs.EOF Then
        MsgBox "Function does not return any values"
        SQL = ""
        Exit Function
    End If


    ' Process Column Headings
    nc = rs.Fields.Count
    ReDim varHdr(nc - 1, 0)
    For i = 0 To rs.Fields.Count - 1
        varHdr(i, 0) = rs.Fields(i).Name
    Next

    ' Get Rows from the Recordset
    nr = rs.RecordCount
    varDat = rs.GetRows

    ' Combing Header and Data and Transpose

    ReDim contentOut(0 To nr, 0 To nc - 1)
    For i = 0 To nc - 1
        contentOut(0, i) = varHdr(i, 0)
    Next




    For i = 1 To nr
        For j = 0 To nc - 1
           contentOut(i, j) = varDat(j, i - 1)



        Next
    Next

  ' Optional solution: Write Output Array to Sheet2
  '  With Sheet2
  '      .Cells.Clear
  '      .Range("A1").Resize(nr, nc) = contentOut
  '  End With


    'Figure out size of calling range which will receive the output array
    Dim nRow As Long: nRow = Application.Caller.Rows.Count
    Dim nCol As Long: nCol = Application.Caller.Columns.Count

    'Error if calling range too small
    If nRow < UBound(contentOut, 1) Or nCol < UBound(contentOut, 2) Then
        'Popup message
        'MsgBox "your range is too small."
        ' or return #VALUE! error
        SQL = "Too small range" 'CVErr(xlValue)
        ' or both or whatever else you want there to happen
        Exit Function
    End If

    'Initialise output array to match size of calling range
    Dim varOut As Variant
    ReDim varOut(1 To nRow, 1 To nCol)
    'And fill it with some background value
    Dim iRow As Long
    Dim iCol As Long
    For iRow = 1 To nRow

        For iCol = 1 To nCol
            varOut(iRow, iCol) = ""   ' or "funny bear", or whatever
        Next
    Next

    'Put content in output array and return
    For iRow = 0 To UBound(contentOut, 1)
        For iCol = 0 To UBound(contentOut, 2)
            varOut(iRow + 1, iCol + 1) = contentOut(iRow, iCol)
        Next
    Next



      SQL = varOut

    'Cleanup
    Erase contentOut
    Erase varHdr
    Erase varDat

    rs.Close
    Set rs = Nothing
    Set cn = Nothing


End Function

Answer 1

It looks like you are not specifying the fields/columns in the join. Both currAddress and curAddress2 look like tables. The SQL should be something like:

strSQL = "SELECT * FROM [Table1] " & _
         "LEFT JOIN  [Table2] ON [Table1].[Field] = [Table2].[Field];"

Are Indeks and Indeks2 your field names? If so, you need to place the field name after the table name:

strSQL = "SELECT * FROM [" & currAddress & "] " & _
         "LEFT JOIN  [" & currAddress2 & "] ON [" & currAddress & "].[Indeks] = [" & currAddress2 & "].[Indeks2];"

Answer 2

I believe 'Indeks' is your common field in the two tables, then strSQL should be this:

strSQL = "SELECT * FROM [" & currAddress & "] " & _ "LEFT JOIN [" & currAddress2 & "] ON [" & currAddress & "].[Indeks] = [" & currAddress2 & "].[Indeks]"