Oracle Running Multiplication - sql

Question

we all know how to generate a running total column with
SELECT id, date, value, sum(value)
OVER (partition by id order by date) total
FROM dual
ORDER BY date
Which will give me something like
ID DATE VALUE TOTAL
1 1/1/14 0.001 0.001
2 2/1/14 0.003 0.004
3 3/1/14 0.002 0.006
Now I want to generate a "running multiplication" which generated 0.001 * 0.004 * 0.006. I know that if I just want the value for the whole multiplication can be done by something like
SELECT exp(sum(ln(value))) from dual
but this one does not work with the partition in oracle. Maybe someone has an idea?
Edit
The desired result would be (don't mind the numbers, they are just dummies, they will not run into an overflow).
ID DATE VALUE TOTAL
1 1/1/14 0.001 0.001
2 2/1/14 0.003 0,000004
3 3/1/14 0.002 0,000000024

Answer 1

The exp(sum(ln())) approach works as long as you add the analytics for the sum() part, not for the exp(). This would give you the product of the original values:
WITH t AS (
SELECT 1 AS id, DATE '2014-01-01' AS dat, 0.001 AS value FROM dual
UNION ALL SELECT 2, DATE '2014-01-02', 0.003 FROM dual
UNION ALL SELECT 3, DATE '2014-01-03', 0.002 FROM dual
)
SELECT id, dat, value, EXP(SUM(LN(value))
OVER (PARTITION BY null ORDER BY dat))
AS total
FROM t
ORDER BY dat;
ID DAT VALUE TOTAL
---------- --------- ---------- ----------
1 01-JAN-14 .001 .001
2 02-JAN-14 .003 .000003
3 03-JAN-14 .002 .000000006
And this would give you the product of the running total:
WITH t AS (
SELECT 1 AS id, DATE '2014-01-01' AS dat, 0.001 AS value FROM dual
UNION ALL SELECT 2, DATE '2014-01-02', 0.003 FROM dual
UNION ALL SELECT 3, DATE '2014-01-03', 0.002 FROM dual
),
u AS (
SELECT id, dat, value, SUM(value)
OVER (PARTITION BY null ORDER BY dat) AS total
FROM t
)
SELECT id, dat, value, total, EXP(SUM(LN(total))
OVER (PARTITION BY null ORDER BY dat)) AS product
FROM u
ORDER BY dat;
ID DAT VALUE TOTAL PRODUCT
---------- --------- ---------- ---------- ----------
1 01-JAN-14 .001 .001 .001
2 02-JAN-14 .003 .004 .000004
3 03-JAN-14 .002 .006 .000000024
Use your own table instead of the CTE obviously; and if you're trying to get the product/sum over multiple values with an ID when change it to partition by id. Using null is to make this work with your sample data.

Answer 2

Unashamedly riffing off this demonstration of a custom aggregate product() function, which supports windowing, you could create your own analytic function to do the calculation for you:
CREATE OR REPLACE TYPE product_total_impl AS OBJECT
(
product NUMBER,
total NUMBER,
product_total NUMBER,
STATIC FUNCTION ODCIAggregateInitialize(ctx IN OUT product_total_impl) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateIterate(SELF IN OUT product_total_impl,
VALUE IN NUMBER) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateMerge(SELF IN OUT product_total_impl,
ctx2 IN product_total_impl) RETURN NUMBER,
MEMBER FUNCTION ODCIAggregateTerminate(SELF IN OUT product_total_impl,
returnvalue OUT NUMBER,
flags IN NUMBER) RETURN NUMBER
);
/
CREATE OR REPLACE TYPE BODY product_total_impl IS
STATIC FUNCTION ODCIAggregateInitialize(ctx IN OUT product_total_impl) RETURN NUMBER IS
BEGIN
ctx := product_total_impl(1, 0, 1);
RETURN ODCIConst.Success;
END ODCIAggregateInitialize;
MEMBER FUNCTION ODCIAggregateIterate(SELF IN OUT product_total_impl,
VALUE IN NUMBER) RETURN NUMBER IS
BEGIN
IF VALUE IS NOT NULL THEN
SELF.product := SELF.product * VALUE;
SELF.total := SELF.total + VALUE;
SELF.product_total := SELF.product_total * SELF.total;
END IF;
RETURN ODCIConst.Success;
END ODCIAggregateIterate;
MEMBER FUNCTION ODCIAggregateMerge(SELF IN OUT product_total_impl,
ctx2 IN product_total_impl) RETURN NUMBER IS
BEGIN
SELF.product := SELF.product * ctx2.product;
SELF.total := SELF.total + ctx2.total;
SELF.product_total := ctx2.product_total * ctx2.total;
RETURN ODCIConst.Success;
END ODCIAggregateMerge;
MEMBER FUNCTION ODCIAggregateTerminate(SELF IN OUT product_total_impl,
returnvalue OUT NUMBER,
flags IN NUMBER) RETURN NUMBER IS
BEGIN
returnvalue := SELF.product_total;
RETURN ODCIConst.Success;
END ODCIAggregateTerminate;
END;
/
CREATE OR REPLACE FUNCTION product_total(x IN NUMBER) RETURN NUMBER
PARALLEL_ENABLE
AGGREGATE USING product_total_impl;
/
Then you can do:
WITH t AS (
SELECT 1 AS id, DATE '2014-01-01' AS dat, 0.001 AS value FROM dual
UNION ALL SELECT 2, DATE '2014-01-02', 0.003 FROM dual
UNION ALL SELECT 3, DATE '2014-01-03', 0.002 FROM dual
)
SELECT id, dat, value,
SUM(value) OVER (PARTITION BY null ORDER BY dat) AS total,
PRODUCT_TOTAL(value) OVER (PARTITION BY null ORDER BY dat) AS product_total
FROM t
ORDER BY dat;
ID DAT VALUE TOTAL PRODUCT_TOTAL
---------- --------- ---------- ---------- -------------
1 01-JAN-14 .001 .001 .001
2 02-JAN-14 .003 .004 .000004
3 03-JAN-14 .002 .006 .000000024
SQL Fiddle with the original product as well.
As before, use your own table instead of the CTE obviously; and if you're trying to get the product/sum over multiple values with an ID when change it to partition by id. Using null is to make this work with your sample data.