ORACLE wm_concat自定义

create or replace type MyConcatImpl as object  
(  
  str VARCHAR2(32767), -- second highest value seen so far  
  static function ODCIAggregateInitialize(sctx IN OUT MyConcatImpl)   
    return number,  
  member function ODCIAggregateIterate(self IN OUT MyConcatImpl,   
    value IN VARCHAR2) return number,  
  member function ODCIAggregateTerminate(self IN MyConcatImpl,   
    returnValue OUT VARCHAR2, flags IN number) return number,  
  member function ODCIAggregateMerge(self IN OUT MyConcatImpl,   
    ctx2 IN MyConcatImpl) return number  
);  
/  
  
create or replace type body MyConcatImpl is   
static function ODCIAggregateInitialize(sctx IN OUT MyConcatImpl)   
return number is   
begin  
  sctx := MyConcatImpl(NULL);  
  return ODCIConst.Success;  
end;  
  
member function ODCIAggregateIterate(self IN OUT MyConcatImpl, value IN VARCHAR2) return number is  
begin  
  if self.str is not null then  
    self.str := self.str || ';' || value;  
  else  
    self.str := value;  
  end if;  
  return ODCIConst.Success;  
end;  
  
member function ODCIAggregateTerminate(self IN MyConcatImpl, returnValue OUT VARCHAR2, flags IN number) return number is  
begin  
  returnValue := self.str;  
  return ODCIConst.Success;  
end;  
  
member function ODCIAggregateMerge(self IN OUT MyConcatImpl, ctx2 IN MyConcatImpl) return number is  
begin  
  if ctx2.str is not null then  
    self.str := self.str || ';' || ctx2.str;  
  end if;  
  return ODCIConst.Success;  
end;  
end;  
/  
create or replace FUNCTION MyConcat(input VARCHAR2) RETURN VARCHAR2   
PARALLEL_ENABLE AGGREGATE USING MyConcatImpl;