php - 如何在多个 PHP 中求和 mysql 值

Question

我喜欢对 $orderfeed_query 中的所有行值求和。但是当我回显 $sum 时，我只得到最后一个循环的总和。

如何在 $sum 变量上添加所有后续循环的总和？我不知道一个订单有多少个循环。

$checkorder = mysql_query("SELECT * FROM orders WHERE  `email` = '$email' ") or die(mysql_error());
while ($row = mysql_fetch_assoc($checkorder)) {
    $orderid = $row["orderid"];
    $check_order = $row["check_order"];

    if($check_order[0] == 1){

        $orderfeed_query = mysql_query("SELECT * FROM orderfeed WHERE `orderid` = '$orderid' AND `product` = '1'") or die(mysql_error());
        while ($row = mysql_fetch_assoc($orderfeed_query)) {
            $signaturewiz = $row["signaturewiz"];
            $flurstueckwiz = $row["flurstueckwiz"];
            $uploadwiz = $row["uploadwiz"];
            $exsignaturewiz = $row["exsignaturewiz"];
            $ibanwiz = $row["ibanwiz"];

            $sum = $signaturewiz+$flurstueckwiz+$uploadwiz+$exsignaturewiz+$ibanwiz;

            echo $sum;

        }
    }   

}
}   

Answer 1

这段代码

$sum = $signaturewiz + $flurstueckwiz + $uploadwiz + $exsignaturewiz + $ibanwiz;

每次都覆盖总和。你必须添加到总和不覆盖

$sum += $signaturewiz + $flurstueckwiz + $uploadwiz + $exsignaturewiz + $ibanwiz;

并在主循环之前声明$sum = 0;