如何将PHP表中的两个值相乘以获得总数？

Question

所以我有一个表显示我的数据库中的数据，我想要在总场中添加，无论如何我会得到数量和价格乘以然后显示到新的总场？

这里是我到目前为止的代码

<?php 
// Connection data (server_address, database, name, poassword) 
$hostdb = 'localhost'; 
$namedb = 'xxxx'; 
$userdb = 'xxxx'; 
$passdb = ''; 

try { 
// Connect and create the PDO object 
$conn = new PDO("mysql:host=$hostdb; dbname=$namedb", $userdb, $passdb); 
$conn->exec("SET CHARACTER SET utf8");  // Sets encoding UTF-8 

// Define and perform the SQL query 
$sql = "SELECT `id`, `wine`, `amount`, `price`, `upc` FROM `wine`"; 
$result = $conn->query($sql); 

// If the SQL query is succesfully performed ($result not false) 
if($result !== false) { 
// Create the beginning of HTML table, and the first row with colums title 
$html_table = '<table border="1" cellspacing="0" cellpadding="2"><tr><th>ID</th>  <th>Wine</th><th>Amount</th><th>Price</th><th>upc</th></tr>'; 

// Parse the result set, and adds each row and colums in HTML table 
foreach($result as $row) { 
    $html_table .= '<tr><td align="center">' .$row['id']. '</td><td align="center">' .$row['wine']. '</td><td align="center">' .$row['amount']. '</td><td align="center">' .$row['price']. '</td><td align="center">' .$row['upc']. '</td></tr>'; 
} 
} 

$conn = null;  // Disconnect 

$html_table .= '</table>';   // ends the HTML table 

echo $html_table;  // display the HTML table 
} 
catch(PDOException $e) { 
echo $e->getMessage(); 
} 
?> 
<a href="/admin/">Admin</a> 

Answer 1

喜欢这个？

'<td>' . $row['amount'] * $row['price'] . '</td>' 

Answer 2

$total_price = $row['amount'] * $row['price']; 

你还需要这些调整：

$html_table = '<table border="1" cellspacing="0" cellpadding="2"><tr><th>ID</th>  <th>Wine</th><th>Amount</th><th>Price</th><th>Total</th><th>upc</th></tr>'; 

以及循环内：

$html_table .= '<tr><td align="center">' .$row['id']. '</td><td align="center">' .$row['wine']. '</td><td align="center">' .$row['amount']. '</td><td align="center">' .$row['price']. '</td><td align="center">' .$row['upc']. '</td><td align="center">' . $total_price . '</td></tr>'; } 

Answer 3

有时显示屏只显示XX * XX在这种情况下，我将包装值如下：

$total = ($row['amount']) * ($row['price']) 

Answer 4

You could easily retrieve the total by calculating it in the query itself. 

    change your sql to: 
    SELECT id, wine, amount, price, upc, (amount*price) as total FROM wine; 

    display it like this: 

    $html_table .= '<tr><td align="center">' .$row['id']. '</td><td align="center">' .$row['wine']. '</td><td align="center">' .$row['amount']. '</td><td align="center">' .$row['price']. '</td><td align="center">' .$row['upc']. '</td> 
<td align="center">' .$row['total']. '</td></tr>';