Connection base avec mysqli

$link = mysqli_connect ($host,$user,$pass,$db) or die ('Erreur : '.mysqli_error() );
mysqli_select_db($link) or die ('Erreur :'.mysqli_error());

<?php   include ('../connexion/connexion.php'); 

$requete="SELECT texte_FR,lien_photo,largeur FROM bienvenue"; 
$result = mysqli_query($requete,$link) or exit ('Erreur : '.mysqli_error() ); 
$row = mysql_fetch_array($result);

<?php
$host = "localhost";
$user = "my_user";
$password =  "my_password";
$bdd = "world";

$link = mysqli_connect($host, $user,$password , $bdd );

/* Vérification de la connexion */
if (mysqli_connect_errno()) {
    printf("Échec de la connexion : %s\n", mysqli_connect_error());
    exit();
}

// requête :
$query = "SELECT Name, CountryCode FROM City ORDER by ID DESC LIMIT 50,5";

if ($result = mysqli_query($link, $query)) {

    /* Récupère un tableau associatif */
    while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
        printf ("%s (%s)\n", $row["Name"], $row["CountryCode"]);
    }

    /* Libération des résultats */
    mysqli_free_result($result);
}else{
//Affichage de l'erreur :
 printf("Errormessage: %s\n", mysqli_error($link));
}

/* Fermeture de la connexion */
mysqli_close($link);
?>

mysqli_free_result($result);
mysqli_close();
exit;
?>

$nb_id = "SELECT COUNT(DISTINCT id) AS compteur FROM europe";
$result = mysql_query($link,$nb_id) or die ('Erreur : '.mysql_error() );
$total = mysql_num_rows($result);
echo $total;

$nb_id = "SELECT COUNT(DISTINCT id) AS compteur FROM europe";
$result = mysqli_query($link,$nb_id) or die ('Erreur : '.mysqli_error($link) );
$total = mysqli_num_rows($result);
echo $total;