dotaz přes 2 tabulky a hodnota NULL

$query = "SELECT id_auta,doba_financovani,najezd, min(basic) as basic, a.* 
           FROM `operak_osobni_auta` o  
           JOIN `osobni_auta` a 
           ON (a.motor = '2.0') and (a.stav = 'aktivni')";
                   
$result = mysqli_query($conn,$query);

if(mysqli_num_rows($result))
{
   while($row = mysqli_fetch_assoc($result)
   {
     ... kod
   }
}

SELECT id_auta,doba_financovani,najezd, min(basic) as basic, a.* 
           FROM `operak_osobni_auta` o  
           JOIN `osobni_auta` a 
           ON `id_auta` = `id`
           WHERE (a.motor = '2.0') and (a.stav = 'aktivni')