oracle 自定義 group 聚合函數

create or replace type CLOB_GROUP_OBJ as object ( 
    sum_string clob, 
    static function ODCIAggregateInitialize(v_self in out CLOB_GROUP_OBJ) return number, 
    member function ODCIAggregateIterate(self in out CLOB_GROUP_OBJ, value in varchar2) return number, 
    member function ODCIAggregateMerge(self in out CLOB_GROUP_OBJ, v_next in CLOB_GROUP_OBJ) return number, 
    member function ODCIAggregateTerminate(self in CLOB_GROUP_OBJ, return_value out clob ,v_flags in number) return number 
) 
/ 
create or replace type body CLOB_GROUP_OBJ is 
    static function ODCIAggregateInitialize(v_self in out CLOB_GROUP_OBJ) return number is 
    begin 
        v_self := CLOB_GROUP_OBJ(null); 
        return ODCICONST.Success; 
    end; 
    member function ODCIAggregateIterate(self in out CLOB_GROUP_OBJ, value in varchar2) return number is 
    begin 
         self.sum_string := self.sum_string || value||'|'; 
         return ODCICONST.Success;
         if self.sum_string<value then 
             self.sum_string:=value; 
         end if;         if self.sum_string>value then 
self.sum_string:=value; 
         end if; 
          
         return ODCICONST.Success; 
    end; 
    member function ODCIAggregateMerge(self in out CLOB_GROUP_OBJ, v_next in CLOB_GROUP_OBJ) return number is 
    begin
         self.sum_string := self.sum_string ||v_next.sum_string; 
         return ODCICONST.Success;
         if self.sum_string<v_next.sum_string then 
             self.sum_string:=v_next.sum_string; 
         end if;
         if self.sum_string>v_next.sum_string then 
             self.sum_string:=v_next.sum_string; 
         end if; 
          
         return ODCICONST.Success; 
    end; 
    member function ODCIAggregateTerminate(self in CLOB_GROUP_OBJ, return_value out clob ,v_flags in number) return number is 
    begin 
         return_value:= self.sum_string; 
         return ODCICONST.Success; 
    end; 
end; 
/ 
create or replace function GROUPCATCLOB(value varchar2) return clob 
    parallel_enable aggregate using CLOB_GROUP_OBJ;