oracle 自定义聚合函数(MAX_O3_8HOUR_ND) 计算最大的臭氧8小时滑动平均值

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 (
--聚合函数的实质就是一个对象
num NUMBER,
var_array type_array,
static function ODCIAggregateInitialize(v_self in out MAX_O3_8HOUR) return number,
--对象初始化
member function ODCIAggregateIterate(self in out MAX_O3_8HOUR, value in number) return number,
--聚合函数的迭代方法(这是最重要的方法)
member function ODCIAggregateMerge(self in out MAX_O3_8HOUR, v_next in MAX_O3_8HOUR) return number,
--当查询语句并行运行时,才会使用该方法,可将多个并行运行的查询结果聚合

member function ODCIAggregateTerminate(self in MAX_O3_8HOUR, return_value out number ,v_flags in number) return number
--终止聚集函数的处理,返回聚集函数处理的结果.
)

create or replace type body MAX_O3_8HOUR is
static function ODCIAggregateInitialize(v_self in out MAX_O3_8HOUR) return number is
begin
--对象初始化
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
--聚合函数的迭代方法(这是最重要的方法)
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
--当查询语句并行运行时,才会使用该方法,可将多个并行运行的查询结果聚合
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
--终止聚集函数的处理,返回聚集函数处理的结果.
--oracle数组序列从1开始

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;