php - 遍历 while 循环并将数字相加

Question

我从数据库获取数据并根据 billing_type 和日期执行计算。我能够正确循环并执行每个日期的计算。不过，我现在正在尝试将计算结果相加。

例如，如果计算结果相等:10、7、30、28

我希望能够将它们相加并显示 75 的结果

这是我的代码:

$sql = "SELECT billing_amount, billed_by, open, SUM(tickets), COUNT(casekey)
        FROM pcnclientreport
        WHERE open = '$date' GROUP BY '$date'";

$res = mysqli_query($conn, $sql);

while($row = mysqli_fetch_assoc($res) ){
    if($row['billed_by'] == 'Month'){ 
        $gsliability = $row['billing_amount'];
    }
    else if ($row['billed_by'] == 'Case'){
        $gsliability = ($row['billing_amount'] * $row['COUNT(casekey)']);
    }
    else if ($row['billed_by'] == 'Ticket'){
        $gsliability = ($row['billing_amount'] * $row['SUM(tickets)']);
    }
}

echo $gsliability

Answer 1

$sql = "SELECT billing_amount, billed_by, open, SUM(tickets), COUNT(casekey)
    FROM pcnclientreport
    WHERE open = '$date' GROUP BY '$date'";

$res = mysqli_query($conn, $sql);

$sum = 0;
while($row = mysqli_fetch_assoc($res) ){

    $gsliability = 0;

    if($row['billed_by'] == 'Month'){ 
        $gsliability = $row['billing_amount'];
    }
    else if ($row['billed_by'] == 'Case'){
        $gsliability = ($row['billing_amount'] * $row['COUNT(casekey)']);
    }
    else if ($row['billed_by'] == 'Ticket'){
        $gsliability = ($row['billing_amount'] * $row['SUM(tickets)']);
    }

    $sum += $gsliability;
}

echo $sum;