$sql = "SELECT *,p.nombre as nombre_producto FROM productos AS p, categorias AS c, areas AS a WHERE p.oferta = 1 AND p.idCategoria = c.idCategoria AND c.idArea = a.idArea AND a.idArea = 4";
$conn->query($sql);
$z = 0;
while ( $rs = $conn->next_rs() ) {
?>