echo date("Y");

<?php
...
$zapytanie = "...";
mysqli_query($db, $zapytanie);
...
?>

SELECT * FROM producent, hurtownia, sklep, serwis
WHERE producent.nr_id = hurtownia.nr_id
AND producent.wyrob_id = serwis.wyrob_id
AND hurtownia.nr_id = sklep.nr_id
AND sklep.nr_id = serwis.nr_id
AND producent.nr_id = 1;

<input type="checkbox" name="text1" value="text2">

$tab = array();
for ($i = 0; $i < 10; $i++) {
    $tab[$i] = rand(-100, 100);
}
foreach ($tab as $x) {
    if ($x < 0) {
        echo "$x ";
    }
}