CREATE TABLE txn (txn_id INT PRIMARY KEY AUTO_INCREMENT, account VARCHAR(64), amount INT);
ALTER TABLE txn ADD INDEX i1 (account);

##</code><code>##

INSERT INTO txn VALUES (NULL, '101', 40167);
INSERT INTO txn VALUES (NULL, '101', 30821);
...

##</code><code>##

INSERT INTO txn VALUES (NULL, '101', -131386);

##</code><code>##

SELECT account, SUM(amount) as total FROM txn GROUP BY account HAVING total <>  0;