Balance column in a HTML table using PHP

Question

I'm developing a personal finance control system and I want to create a balance column similar to a Bank Statement. My data is stored in a MySQL database with the following structure:

ID	Type	Date	Description	Amount
01	D	01/02/2024	Transaction 1	150,00
02	D	03/02/2024	Transaction 2	250,00
03	D	05/02/2024	Transaction 3	50,00
04	C	06/02/2024	Transaction 4	980,00

I need to create a column that stores the previous balance from a query. Each row will update this column with the current balance. Here's an example (assuming that the previous balance is 250.00):

ID	Type	Date	Description	Amount	Balance
01	D	01/02/2024	Transação 1	-150,00	100,00
02	D	03/02/2024	Transação 2	-250,00	-150,00
03	D	05/02/2024	Transação 3	-50,00	-200,00
04	C	06/02/2024	Transação 4	980,00	780,00

That's what I'm doing in PHP:

$transacoes = '
<table id="tabAccountDetails" class="table lms_table_active" style="width:100%">
    <thead>
        <tr>
            <th scope="col" hidden>#</th>
            <th scope="col">Date</th>
            <th scope="col">Description</th>
            <th scope="col">Amount</th>
            <th scope="col">Balance</th>
            
        </tr>
    </thead>
    <tbody>';
$earlierBalance= 0;
$saldo = 0;
while ($reg = mysqli_fetch_assoc($res)) {
    if ($saldoAnterior == 0) {
        $earlierBalance = $reg["EarlierBalance"];
        $balance = $reg["TransactionAmount"] + $earlierBalance ;

    } else {
        $balance = $reg["TransactionAmount"] + $balance;

    }
    $transactionId = $reg["TransactionId"];
    $account = $reg["AccountName"];
    $description = $reg["TransactionDescription"];
    $date = $reg["TransactionDate"];
    $amount = $reg["TransactionAmount"];
    
    $transacoes .= '
    <tr>
        <td>' . $transactionId . '</td>
        <th scope="row">' . $date . '</th>
        <td>' . $description . '</td>
        <td>' . number_format($ammount, 2, ",", ".") . '</td>
        <td>' . number_format($saldo, 2, ",", ".") . '</td>
    </tr>';
}
$transacoes .= '
    </tbody>
</table>';
echo $transacoes;

For some reason, it is not correctly updating for all rows returned from the database. This is the query I'm using to select the transactions:

SELECT t.TransactionId, 
        t.AccountId, 
        a.AccountName,
        DATE_FORMAT(t.TransactionDate, '%d/%m/%Y') TransactionDate, 
        t.TransactionDescription, 
        t.TransactionType,
        t.TransactionAmount,
        (select SUM(if(TransactionType = 'C', TransactionAmount, TransactionAmount*-1)) 
            FROM  tbtransactions
            WHERE UserId = $userId AND AccountId = $idConta AND TransactionDate < '$initialDate') EarlierBalance
        FROM tbtransactions t
        INNER JOIN tbaccount a ON a.AccountId = t.AccountId
        WHERE t.UserId = $userId AND t.TransactionDate BETWEEN '$initialDate' AND '$finalDate'  
        ORDER BY t.TransactionDate

Can somebody give me any north or help regarding the best way to do it?