我用 php 制作了一个游戏，人们可以在其中升级他们的东西，钱将从他们的帐户中扣除。但当货币值(value)变低时，它就会变成负值，元素就会升级。这是代码:
<?php
session_start();
include_once 'dbconnect.php';
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "dbtest";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
if(!isset($_SESSION['user']))
{
header("Location: index.php");
}
?>
</html>
<head>
<body bgcolor="black">
<?php echo "<font color=\"#49fb35\" size=\"5\">Update Firewall Software $300</font><br>"; ?>
<a href="firewall.php"><font color="#49fb35" size="5">Upgrade Firewall.exe for $300</font></a>
</head>
</html>
货币值(value)低时如何停止升级？
最佳答案
您可以使用 PHP 来验证该值是否大于 0，方法是:
$query1 = "SELECT * from users WHERE user_id=".$_SESSION['user'];
$result = mysql_query($query1);
while($row = mysql_fetch_array($result)) {
// Get money from column
$money = $row['money'];
}
if($money >= 300) {
$query = "UPDATE users SET firewall = firewall + 1, money = money - 300 WHERE user_id=".$_SESSION['user'];
$update = mysqli_query($conn,$query);
} else {
// Prints error
echo 'Money is not enough to upgrade';
}
我不确定您使用的变量名称，您可以相应更改，希望这有帮助!
关于php - 固定货币值(value)为负，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34972798/