code: public RestQueryResult addColumn( String name,
                                        String type ) {
          if (!StringUtil.isBlank(name)) {
              columns.put(name, type);
          }
          return this;
      }
docs: Adds a new column to this result.
  
  @param name a {@code non-null} string, the name of the column
  @param type a {@code non-null} string, the type of the column
  @return this instance