PHP连接数据库并读取数据库中的内容

<?phpheader("Content-type:text/html;charset=utf-8");$servername = "服务器地址";//MySQL默认为localhost，端口号3306$username = "用户名";$password = "密码";$dbname = "数据库名称";// 创建连接$conn = new mysqli($servername, $username, $password, $dbname);// Check connectionif ($conn->connect_error) { die("连接失败: " . $conn->connect_error);}$sql = "SELECT 列名1, 列名2 FROM 表";$result = $conn->query($sql);if ($result->num_rows > 0) { // 输出数据 while($row = $result->fetch_assoc()) { echo "列名1: " . $row["列名1"]. " 列名2: " . $row["列名2"]."<br>"; }} else { echo "0 结果";}$conn->close();?>