oracle 自定義聚合函數(MAX_O3_8HOUR_ND) 計算最大的臭氧8小時滑動平均值

create or replace function MAX_O3_8HOUR_ND(value NUMBER) return NUMBER
     parallel_enable aggregate using MAX_O3_8HOUR;

CREATE OR REPLACE TYPE MAX_O3_8HOUR    as object (
--聚合函數的實質就是一個對象
     num NUMBER,
     var_array type_array,
     static function ODCIAggregateInitialize(v_self in out MAX_O3_8HOUR) return number,
     --對象初始化
     member function ODCIAggregateIterate(self in out MAX_O3_8HOUR, value in number) return number,
     --聚合函數的迭代方法(這是最重要的方法)
     member function ODCIAggregateMerge(self in out MAX_O3_8HOUR, v_next in MAX_O3_8HOUR) return number,
     --當查詢語句並行運行時,才會使用該方法,可將多個並行運行的查詢結果聚合

     member function ODCIAggregateTerminate(self in MAX_O3_8HOUR, return_value out number ,v_flags in number) return number
     --終止聚集函數的處理,返回聚集函數處理的結果.
)

create or replace type body MAX_O3_8HOUR is
     static function ODCIAggregateInitialize(v_self in out MAX_O3_8HOUR) return number is
     begin
         --對象初始化
         v_self := MAX_O3_8HOUR(0,type_array(0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0,
           0,0,0,0,0,0,0,0,0,0));
         return ODCICONST.Success;
     end;
     member function ODCIAggregateIterate(self in out MAX_O3_8HOUR, value in number) return number is
    begin
          --聚合函數的迭代方法(這是最重要的方法)
          self.num:=self.num+1;
          self.var_array(self.num):=value;

          return ODCICONST.Success;
     end;
     member function ODCIAggregateMerge(self in out MAX_O3_8HOUR, v_next in MAX_O3_8HOUR) return number is
     begin
          --當查詢語句並行運行時,才會使用該方法,可將多個並行運行的查詢結果聚合
          return ODCICONST.Success;

     end;
     member function ODCIAggregateTerminate(self in MAX_O3_8HOUR, return_value out number ,v_flags in number) return number is
     n number;
     re number;
     hour8 number;
     begin
       --終止聚集函數的處理,返回聚集函數處理的結果.
       --oracle數組序列從1開始
          
          n:=self.num-7;
          re:=0;
          for i in 1..n loop  
              hour8:=0;
              for j in  i..(i+7) loop
                  hour8:=hour8+self.var_array(j);
              end loop;
              
              IF re<hour8 THEN
                  re:=hour8;
              END IF;
          end loop; 
  
          return_value:=ceil(re/8);
          return ODCICONST.Success;
     end;
end;