search.php?lic=0§ion=1,2&type=1,2,3,4
SELECT `id`
FROM `content`
WHERE lic='".$lic."' AND section='".$section."' AND type='".$type."'
$req = $mysqli->prepare(
"SELECT `id` FROM `content` ".
"WHERE ('' = ? OR `lic` = ?) ".
"AND ('' = ? OR `selection` = ?) ".
"AND ('' = ? OR `type` = ?)"
);
$req->bind_param('ssssss', $lic, $lic, $selection, $selection, $type, $type);