code: protected void processSelectBody(SelectBody selectBody, int level) {
          if (selectBody instanceof PlainSelect) {
              processPlainSelect((PlainSelect) selectBody, level + 1);
          } else if (selectBody instanceof WithItem) {
              WithItem withItem = (WithItem) selectBody;
              if (withItem.getSelectBody() != null) {
                  processSelectBody(withItem.getSelectBody(), level + 1);
              }
          } else {
              SetOperationList operationList = (SetOperationList) selectBody;
              if (operationList.getSelects() != null && operationList.getSelects().size() > 0) {
                  List<SelectBody> plainSelects = operationList.getSelects();
                  for (SelectBody plainSelect : plainSelects) {
                      processSelectBody(plainSelect, level + 1);
                  }
              }
          }
      }
docs: 处理selectBody去除Order by
  
  @param selectBody