public function requested_link_ids_sql()
{
// Multiple link IDs passed in link_ids[]=... . . .
$link_ids = isset($_REQUEST['link_ids']) ? $_REQUEST['link_ids'] : array();
// Or single in link_id=...
if (isset($_REQUEST['link_id'])) {
array_push($link_ids, $_REQUEST['link_id']);
}
// Filter for safe use in MySQL queries.
$link_ids = $this->sanitize_ids_sql($link_ids);
// Convert to MySQL list literal.
return "('" . implode("', '", $link_ids) . "')";
}