MySQLi：无法加载动态库

Question

伙计们。 我已经有几天尝试从php脚本访问MariaDB了，但是没有成功。这是代码（我从w3schools复制了代码）

<?php
$servername = "localhost";
$username = "";
$password = "";

//Se crea la coneccion con la Base de Datos
$conn = new mysqli($servername,$username,$password);
//Se asegura que todo este correcto
function conectar(){
    if (mysqli_connect_error()){
    die ("Coneccion a Base de Datos fallida: ".mysqli_connect_error());
    }
}?>

当我尝试执行它时，结果如下：

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/lib/php/20151012/mysqli.so'- /usr/lib/php/20151012/mysqli.so: undefined symbol: mysqlnd_connect in Unknown on line 0
PHP Fatal error:  Uncaught Error: Class 'mysqli' not found in /var/www/html/lisa.php:7
Stack trace:
#0 {main}
 thrown in /var/www/html/lisa.php on line 7