How to make an INNER JOIN with two tables in different banks?

I have two different banks that I make the connection in the following way:

date_default_timezone_set('America/Sao_Paulo');
abstract class BancoDados
{
const host = 'localhost';
const novoweb = 'novoweb';
const WebAccount = 'Web_Account';
const Member = 'Member';
const user = 'usuario';
const password = 'senha';
static function conectarW()
{
    try 
    {
        $pdoW = new PDO("mysql:host=".self::host.";dbname=".self::novoweb.";charset=utf8", self::user, self::password);
        $pdoW->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $pdoW;
    } catch(PDOException $e) {
        echo 'ERROR: ' . $e->getMessage();
    }
}
static function conectarWA()
{
    try 
    {
        $pdoWA = new PDO("mysql:host=".self::host.";dbname=".self::WebAccount.";charset=utf8", self::user, self::password);
        $pdoWA->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $pdoWA;
    } catch(PDOException $e) {
        echo 'ERROR: ' . $e->getMessage();
    }
}
}

I have two values in the novoweb database in the shopweb table with the id and nome columns, where id I enter the Web_Account database in the GameTail table in the ItemIdx column but I do not know how do INNER JOIN because I make the query like this.

static function historicoshopweb($pdoWA,$id,$admin)
{
    try {
        if ($admin == 1) {
            $historico = $pdoWA->prepare("SELECT * FROM GameTail  ORDER BY RegDate DESC");
            $historico->execute();
        } else {
            $historico = $pdoWA->prepare("SELECT * FROM GameTail WHERE IdIdx = :id ORDER BY RegDate DESC");
            $historico->bindValue(":id",$id);
            $historico->execute();
        }
            $historicos = $historico->fetchAll(PDO::FETCH_OBJ);

            return $historicos;

    } catch (PDOException $e) {
        echo "ERROR: ".$e->getMessage();
    }
}

Then I want instead of the ItemIdx to appear the name of the item.