如何計算PHP中while循環內的乘法值？

Question

我有一個while循環顯示數據庫中的數據。現在我想將一行中的兩個值相乘，並將結果顯示在同一行中，同樣的方式將這些值相乘並在每一行中顯示結果。我沒有得到結果。誰能幫我？我是PHP新手。

while($row = mysql_fetch_array($result)) 
{ 
    echo "<tr>"; 
    echo "<td class='alt'>" . $row['id'] . "</td>"; 
    echo "<td>" . $row['item'] . "</td>"; 
    echo "<td>" . $row['amount'] . "</td>"; 
    $ss=$row['amount']; 
    echo '<td >'.'<input type="checkbox" name="status" value="" >'.'</td>'; 
    echo '<td >'.'<input type="text" name="qty">'.'</td>'; 
    echo "<td>" . $rr1 . "</td>"; 
    echo "</tr>"; 
} 

Answer 1

從哪裏得到$rr1？

你可以有

echo "<td>" . $row['item'] * $row['amount'] . "</td>";

希望這是你想要的...

Answer 2

你可以嘗試

printf('amount is %d',$row['item'] * $row['amount']); 

reference

Answer 3

如下嘗試：

while($row = mysql_fetch_array($result)) 
    { 
     echo "<tr>"; 
     echo "<td class='alt'>" . $row['id'] . "</td>"; 
     echo "<td>" . $row['item'] . "</td>"; 
     echo "<td>" . $row['amount'] . "</td>"; 
     echo "<td>" .($row['item'] * $row['amount']). "</td>"; 
     echo "</tr>"; 
    } 

Answer 4

更改查詢作爲

$result= mysql_query("Select id, item, amount, (item * amount) total 
from table_name"); 

然後在while循環

while($row = mysql_fetch_array($result)) 
    { 
     echo "<tr>"; 
     echo "<td >" . $row['id'] . "</td>"; 
     echo "<td>" . $row['item'] . "</td>"; 
     echo "<td>" . $row['amount'] . "</td>"; 
     echo "<td>" .($row['total'] "</td>"; 
     echo "</tr>"; 
    }