php连接mysql并执行sql语句

可以使用 PHP 中的 mysqli 扩展或 PDO 扩展来连接 MySQL 数据库并执行 SQL 语句。

使用 mysqli 扩展：

// 配置数据库连接信息
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);

// 检查连接是否成功
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

// 执行 SQL 查询
$sql = "SELECT * FROM users";
$result = mysqli_query($conn, $sql);

// 输出查询结果
if (mysqli_num_rows($result) > 0) {
    while($row = mysqli_fetch_assoc($result)) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
    }
} else {
    echo "0 results";
}

// 关闭连接
mysqli_close($conn);

使用 PDO 扩展：

// 配置数据库连接信息
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置 PDO 错误模式为异常
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch(PDOException $e) {
    echo "Connection failed: " . $e->getMessage();
}

// 执行 SQL 查询
$sql = "SELECT * FROM users";
$result = $conn->query($sql);

// 输出查询结果
if ($result->rowCount() > 0) {
    foreach($result as $row) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
    }
} else {
    echo "0 results";
}

// 关闭连接
$conn = null;