Hi,
Suppose I have a database:
CREATE TABLE data (timestamp INTEGER, amount INTEGER);
INSERT INTO data VALUES(1,10);
INSERT INTO data VALUES(2,20);
INSERT INTO data VALUES(3,5);
INSERT INTO data VALUES(4,2);
...
Now I want to see the sum up to the timestamp:
SELECT
timestamp,(SELECT sum(amount)
FROM data as d
WHERE d.timestamp<=data.timestamp)
FROM data ORDER BY timestamp;
This works fine for small data sets. But it is obviously
a quadratic problem. Is there a more efficient way to do
the same thing?
Michael
