There are pros and cons for both of them:
pros:
1) the first approach is fast and easy during calculation, as it pulls out the totals which are physically stored.
2) the second approach does not have any physical impact to the database or cause any additional operations. And in real cases, the requirements are specific, like for a certain number of G/L Account in a given period of time. These could help to narrow down the transactions which can be profitable in reality.
cons:
1) the first approach is costly to maintain during transaction update. And it has a physical, permanent impact to the database and front end system.
2) the second approach needs to calculate every result from the transactions every time it is needed, which could be very large and slow too.
Never mind, I just thought it’s an idea worth a look.