How to find running product

Question

In oracle, is there a way we can find running product ?
create table an_t(col2 number)
insert into an_t(col2) values (3);
insert into an_t(col2) values (2);
insert into an_t(col2) values (4);
commit;
So we want to see in another column
result like this:
3*2 = 6
6*4 = 24 (above result multiplied by next row value)

Answer 1

You could use Tubby's suggestion. Although it's pretty accurate, still there is a chance of losing precision. Another suggestion is writing your own PROD function using ODCI interface:
create or replace
  type prod_type as object(
                           prod number,
                           static function ODCIAggregateInitialize(
                                                                   sctx in out prod_type
                             return number,
                           member function ODCIAggregateIterate(
                                                                self  in out prod_type,
                                                                value in     varchar2
                             return number,
                           member function ODCIAggregateTerminate(
                                                                  self        in  prod_type,
                                                                  returnvalue out number,
                                                                  flags in number
                             return number,
                           member function ODCIAggregateMerge(
                                                              self in out prod_type,
                                                              ctx2 in     prod_type
                             return number
create or replace
  type body prod_type
    is
      static function ODCIAggregateInitialize(
                                              sctx in out prod_type
        return number
        is
        begin
            sctx := prod_type(null) ;
            return ODCIConst.Success ;
      end;
      member function ODCIAggregateIterate(
                                           self  in out prod_type,
                                           value in     varchar2
        return number
        is
        begin
            self.prod := nvl(self.prod,1) * value ;
            return ODCIConst.Success;
      end;
      member function ODCIAggregateTerminate(
                                             self        in  prod_type,
                                             returnvalue out number,
                                             flags       in  number
        return number
        is
        begin
            returnValue := self.prod;
            return ODCIConst.Success;
        end;
      member function ODCIAggregateMerge(
                                         self in out prod_type ,
                                         ctx2 in     prod_type
        return number
        is
        begin
            self.prod := self.prod * ctx2.prod;
            return ODCIConst.Success;
        end;
end;
create or replace
  function prod(
                input number
    return number
    deterministic
    parallel_enable
    aggregate using prod_type;
/Now:
select  col1,
        prod(col2) over (order by col1 asc) as running_product
  from  an_t
      COL1 RUNNING_PRODUCT
         1               3
         2               6
         3              24
SQL> SY.