How to show bank balance through transactions in laravel

Question

I have Bank table and transaction table. The relationship is one-to-many, so a bank may have many transactions. Transaction table has the bank foreign key(bank_id). and each transaction has a column 'type' which is either credit or debit. I want to show each bank balance based on its transactions.

Here are my questions:

1. How to select a specific bank?
2. How to calculate the balance for a bank?
3. Should I calculate it in controller, model, or view? which one is the best?

Here is transactions table: thanks in advance!

Answer 1

I'm not sure what you are trying to do. You'd select a bank like

$bank = Bank::find(2);

and you could do something like

$bank->transactions->sum('amount');