Php 尝试将每行的2个列值相乘&；打印所有行的总和

我的目标是计算出股票的总价值

Table name: Stock
Column names: cost(representing an items cost), s_count(representing quantity).

成本乘以s_计数将得出每个项目的总价值。 我将如何将这些列相乘，然后将所有行的结果相加以得到总数

$selectstock=$db->query("SELECT * FROM stock");
$result = $db->query('SELECT SUM(s_count) AS value_sum FROM stock'); 
$rowes = mysql_fetch_assoc($result); 
$sum = $rowes['value_sum'];
$result2 = $db->query('SELECT SUM(amountfailed) AS value_sum FROM stock'); 
$rowes2 = mysql_fetch_assoc($result2); 
$sum2 = $rowes2['value_sum'];
$uparts = mysql_num_rows($selectstock);
$value = // how do i do this?
print "<h3>Stock overview..</h3><br />
<div><p><br />
Amount of unique parts in stock: {$uparts}<br />
total quantity of stock: {$sum}<br />
Current value of all stock: {$value}<br />
Amount of parts failed: {$sum2}<br />";

然后，

$value

需要是20*5+2*10

所以$value将返回185。

这是您想要的吗

SELECT SUM(s_count*cost) AS value_sum
FROM stock

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如果您的意思是

$value=$db->query（“选择SUM（s_count*cost）作为股票的value_SUM”）

然后$value将打印为

资源id#13

20*5，但2*10。。。嗯?？

SELECT SUM(s_count*cost) AS value_sum
FROM stock