code: public static void addAggregateFunctions(String functions){
          if(StringUtil.isNotEmpty(functions)){
              String[] funs = functions.split(",");
              for (int i = 0; i < funs.length; i++) {
                  AGGREGATE_FUNCTIONS.add(funs[i].toUpperCase());
              }
          }
      }
docs: 添加到聚合函数，可以是逗号隔开的多个函数前缀
  
  @param functions