fetcth.php

<?php

$s = 'Iñtërnâtiônàlizætiøn-р X';

$pdo = new PDO('mysql:host=localhost;dbname=fa', '...', '...', [
    PDO::MYSQL_ATTR_INIT_COMMAND => 'SET CHARACTER SET utf8',
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION
]);
$res = $pdo->query('SELECT label FROM connectors WHERE id = 18', PDO::FETCH_COLUMN, 0);
$sDB = $res->fetchColumn();

echo "s  : ".mb_detect_encoding($s)."\n";
echo "sDB: ".mb_detect_encoding($sDB)."\n";

Output:

s : UTF-8
sDB: UTF-8