SQL语句提示类型不匹配

品名拼接C: combstr("coris_cx","f21","提单号9",[提单号9])

Public Function CombStr(TableName As String, FieldName As String, GroupField As String, GroupValue As String) As String


    Dim ResultStr As String
    Dim rs As DAO.Recordset
    Dim Str As String
    Str = "SELECT " & FieldName & " FROM " & TableName & " WHERE " & GroupField & "='" & GroupValue & "'"
    Set rs = CurrentDb.OpenRecordset(Str)






    If rs.RecordCount > 0 Then
        Do While Not rs.EOF
            ResultStr = ResultStr & "," & rs.Fields(0).Value
            rs.MoveNext
        Loop
    End If
    If ResultStr <> "" Then ResultStr = Mid(ResultStr, 2)
    CombStr = ResultStr


End Function