Multiply with Previous Value from One colum in Oracle SQL - oracle

Question

I have the following result, which is easily calculated in Excel, but how to do it in Oracle, the result is the following, based on a previous select and comes from one column,
Result from select Expected result
1.62590
0.60989 0.991620151
0.83859 0.831562742
the result is based on 1.62590 * 0.60989 = 0.991620151,
1.62590 * 0.60989 * 0.83859 = 0.831562742

Answer 1

You can use:
SELECT id,
result,
EXP(SUM(LN(result)) OVER (ORDER BY id)) AS expected
FROM table_name;
Note: Use any other column instead of id to give the appropriate ordering or, if your rows are already ordered, use the ROWNUM pseudo-column instad of id.
Which, for the sample data:
CREATE TABLE table_name (id, Result) AS
SELECT 1, 1.62590 FROM DUAL UNION ALL
SELECT 2, 0.60989 FROM DUAL UNION ALL
SELECT 3, 0.83859 FROM DUAL;
Outputs:
ID
RESULT
EXPECTED
1
1.6259
1.62590000000000000000000000000000000001
2
.60989
.9916201510000000000000000000000000000026
3
.83859
.8315627424270900000000000000000000000085
fiddle

Answer 2

One option is to use a recursive CTE; it, though, expects that sample data can be sorted, somehow, so I added the ID column which starts with 1, while other values are incremented by 1:
Sample data:
SQL> with
2 test (id, col) as
3 (select 1, 1.62590 from dual union all
4 select 2, 0.60989 from dual union all
5 select 3, 0.83859 from dual
6 ),
Query begins here:
7 product (id, col, prod) as
8 (select id, col, col
9 from test
10 where id = 1
11 union all
12 select t.id, t.col, t.col * p.prod
13 from test t join product p on p.id + 1 = t.id
14 )
15 select id,
16 round(prod, 10) result
17 from product;
ID RESULT
---------- ----------
1 1,6259
2 ,991620151
3 ,831562742
SQL>

Answer 3

You can use a MODEL clause:
SELECT *
FROM (SELECT ROW_NUMBER() OVER (ORDER BY id) AS rn, result FROM table_name)
MODEL
DIMENSION BY (rn)
MEASURES ( result, 0 AS expected)
RULES (
expected[rn] = result[cv()] * COALESCE(expected[cv()-1], 1)
)
order by rn;
Which, for the sample data:
CREATE TABLE table_name (id, Result) AS
SELECT 1, 1.62590 FROM DUAL UNION ALL
SELECT 2, 0.60989 FROM DUAL UNION ALL
SELECT 3, 0.83859 FROM DUAL;
Outputs:
RN
RESULT
EXPECTED
1
1.6259
1.6259
2
.60989
.991620151
3
.83859
.83156274242709
fiddle