SQLite Efficient Running Total - sqlite

Question

I have a table of transactions in SQLite
number date Category Amount runningBalance
I want the running balance column to have a running sum of the amount column after the table is sorted by Date first and number second.
I can do this with a select when reading. But this table has the potential to get very large and I don't want to recalculate every time. I want to make a trigger where all the transactions following (by date then number) the inserted/edited transaction have their runningBalance value updated.
This will mean that the calculations are reduced... as more recent transactions are likely to be edited more often, and older ones rarely. It also will spread the computation over writes so that reads are near instant.
Can anyone provide assistance on how to set up such a trigger?
so far this is what I have but it does not give desired results. And recalculates all every time. Not just the ones following the change.
CREATE TRIGGER RunningTotal AFTER UPDATE ON Transactions FOR EACH ROW
BEGIN
UPDATE Transactions
SET RunningBalance = (
SELECT (
SELECT sum(Amount)
FROM TopInfo t2
WHERE t2.Date <= t1.Date
)
FROM Transactions t1
);
END;
Thanks!

Answer 1

I've managed to find a way that works. Not sure how efficient it is though. Love to hear if anyone knows a more efficient way to update the Balance column.
CREATE TRIGGER Balance AFTER UPDATE OF Amount ON Transactions FOR EACH ROW
BEGIN
UPDATE Transactions
SET Balance = (
SELECT Balance
FROM (
SELECT TransactionID,
(
SELECT sum(t2.Amount)
FROM Transactions t2
WHERE t2.Date <= t1.Date
ORDER BY Date
)
AS Balance
FROM Transactions t1
WHERE TransactionID = Transactions.TransactionID
ORDER BY Date
)
)
WHERE Transactions.Date >= NEW.Date;
END;
UPDATE:
CREATE TRIGGER Balance AFTER UPDATE OF Amount ON Transactions FOR EACH ROW
BEGIN
UPDATE Transactions
SET Balance = (
SELECT Balance
FROM (
SELECT TransactionID,
(
SELECT sum(t2.Amount)
FROM Transactions t2
WHERE CASE WHEN t2.Date = t1.Date THEN t2.TransactionID <= t1.TransactionID ELSE t2.Date <= t1.Date END
ORDER BY Date,
TransactionID
)
AS Balance
FROM Transactions t1
WHERE TransactionID = Transactions.TransactionID
ORDER BY Date,
TransactionID
)
)
WHERE Transactions.Date >= NEW.Date;
END;
I've Done Some more with running total and have come up with 2 ways. The second is much slower than the first. Any ideas why???
method 1
SELECT TransactionID,Date, Account, Amount,
(SELECT sum(t2.Amount)
FROM Transactions t2
WHERE
CASE WHEN t2.Date = t1.Date
THEN t2.TransactionID <= t1.TransactionID
AND t2.Account == t1.Account
ELSE t2.Date <= t1.Date
AND t2.Account == t1.Account
END
ORDER BY Date, TransactionID)
AS Balance
FROM Transactions t1
ORDER BY Date, TransactionID
Method2
SELECT n.TransactionID, n.Date, n.Account, n.Amount,
SUM(o.Amount) As running_total
FROM Transactions n LEFT JOIN Transactions o
ON (
CASE WHEN o.Date = n.Date
THEN n.TransactionID >= o.TransactionID
AND o.Account == n.Account
ELSE n.Date >= o.Date
AND o.Account == n.Account
END
)
GROUP BY n.Account, n.Date, n.TransactionID
ORDER BY n.Date, n.TransactionID;