docs: public String explain(Where where) throws SqlParseException {
          List<String> codes = new ArrayList<String>();
          while (where.getWheres().size() == 1) {
              where = where.getWheres().getFirst();
          }
          explainWhere(codes, where);
          String relation = where.getConn().name().equals("AND") ? " && " : " || ";
          return Joiner.on(relation).join(codes);
      }