docs: public void sqlToCount(Select select, String name) {
          SelectBody selectBody = select.getSelectBody();
          // 是否能简化count查询
          List<SelectItem> COUNT_ITEM = new ArrayList<SelectItem>();
          COUNT_ITEM.add(new SelectExpressionItem(new Column("count(" + name +")")));
          if (selectBody instanceof PlainSelect && isSimpleCount((PlainSelect) selectBody)) {
              ((PlainSelect) selectBody).setSelectItems(COUNT_ITEM);
          } else {
              PlainSelect plainSelect = new PlainSelect();
              SubSelect subSelect = new SubSelect();
              subSelect.setSelectBody(selectBody);
              subSelect.setAlias(TABLE_ALIAS);
              plainSelect.setFromItem(subSelect);
              plainSelect.setSelectItems(COUNT_ITEM);
              select.setSelectBody(plainSelect);
          }
      }