code: public SQLSelect column(final int _tableIndex,
                              final String _columnName)
      {
          columns.add(new Column(tablePrefix, _tableIndex, _columnName));
          return this;
      }
docs: Appends a selected column <code>_name</code> for given
  <code>_tableIndex</code>.
  
  @param _tableIndex index of the table
  @param _columnName name of the column
  @return this SQL select statement
  @see #columns