$date1_result = mysql_query("SELECT interface, status FROM router WHERE name=\"$get_name\"
       AND date=\"$date1\" AND interface IS NOT NULL AND status IS NOT NULL ORDER BY status DESC ");

  <?php

    $t1 = array("eth0" => "up", "eth1" => "up", "eth2" => "up");
    $t2 = array("eth0" => "up", "eth1" => "up", "eth2" => "down");

    print_r($t2);
    
    $result1 = array_diff_assoc($t1, $t2);
    $result2 = array_diff_assoc($t2, $t1);
    
    if (empty($result1) && empty($result2)) {
       echo ("keine Veraenderungen im Zeitraum");
    }

    $result3 = array_diff_key($t1, $t2);
    $result4 = array_diff_key($t2, $t1);
    
    foreach ($result1 as $key => $value) {
         echo "Zeitpunkt 1: " . $key . " enthaelt den Wert: " . $value . "
";
    }
    
    echo ("
");
    
    foreach ($result2 as $key => $value) {
         echo "Zeitpunkt 2: " . $key . " enthaelt den Wert: " . $value . "
";
    }


    foreach ($result3 as $key => $value) {
                 echo "weggefallen: " . $key . "
";
    }

    foreach ($result4 as $key => $value) {
                 echo "hinzugekommen: " . $key . " enthaelt den Wert: " . $value . "
";
    }


  ?>