php查询mysql数据库代码

<?php
// 连接到MySQL数据库
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检查数据库连接是否成功
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

// 执行查询语句
$sql = "SELECT * FROM table_name";
$result = mysqli_query($conn, $sql);

// 检查查询结果是否为空
if (mysqli_num_rows($result) > 0) {
    // 输出每一行数据
    while ($row = mysqli_fetch_assoc($result)) {
        echo "id: " . $row["id"] . " - 名称: " . $row["name"] . "<br>";
    }
} else {
    echo "没有查询到数据";
}

// 关闭数据库连接
mysqli_close($conn);
?>