code: private ResultSet getVersionColumnsOrBestRowIdentifier() throws SQLException {
      String sql = VERSION_AND_IDENTIFIER_COLUMNS_SELECT_STATEMENT + FROM_STATEMENT_WITHOUT_RESULTS;
  
      CloudSpannerPreparedStatement statement = prepareStatement(sql);
      return statement.executeQuery();
    }
docs: A simple private method that combines the result of two methods that return exactly the same
  result
  
  @return An empty {@link ResultSet} containing the columns for the methods
  {@link DatabaseMetaData#getBestRowIdentifier(String, String, String, int, boolean)} and
  {@link DatabaseMetaData#getVersionColumns(String, String, String)}
  @throws SQLException