php - 如何从 php mysql 中的先前记录获取总计

Question

我有一个问题:

count this id no 1 = usage/nod
count this id no 2 = (usage[id1]+usage[id2])/(nod[id1]+nod[id2])
count this id no 3 = (usage[id1]+usage[id2]+usage[id3])/(nod[id1]+nod[id2]+nod[id3])

等等...

“usage/nod”是数据库中的一个字段。

如何使用 PHP 和 MySQL 进行计数？

Answer 1

$total_usage = 0;
$total_nod = 0;

while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
    $total_usage += $row['usage'];
    $total_nod += $row['nod'];
    $div = $total_usage/$total_nod;
    echo "count this id no $row[id] = $div\n";
}