do not try to update filter triggers if nothing was triggered

classes/rssutils.php

@@ -783,9 +783,12 @@ class RSSUtils {
 
 				$matched_filter_ids = implode(",", array_map(function($f) { return $f['id']; }, $matched_filters));
 
-				$fsth = $pdo->prepare("UPDATE ttrss_filters2 SET last_triggered = NOW() WHERE 
+
+				if ($matched_filter_ids) {
+					$fsth = $pdo->prepare("UPDATE ttrss_filters2 SET last_triggered = NOW() WHERE 
 							   id IN (?) AND owner_uid = ?");
-				$fsth->execute([$matched_filter_ids, $owner_uid]);
+					$fsth->execute([$matched_filter_ids, $owner_uid]);
+				}
 
 				if (Debug::get_loglevel() >= Debug::$LOG_EXTENDED) {
 					Debug::log("matched filters: ", Debug::$LOG_VERBOSE);