public function updateStatisticsForAllDays()
 {
     $projects = Project::fetchActiveIds($this->conn);
     foreach ($projects as $projectId) {
         $participants = $this->conn->fetchAll('SELECT p.`peopleNum`, p.`createdAt`, a.`id` AS `areaId` ' . 'FROM `' . EdkTables::PARTICIPANT_TBL . '` p ' . 'INNER JOIN `' . CoreTables::AREA_TBL . '` a ON a.id = p.areaId ' . 'WHERE a.projectId = :projectId ORDER BY p.`createdAt`', [':projectId' => $projectId]);
         $total = 0;
         $lastDay = null;
         $first = true;
         $areas = [];
         foreach ($participants as $participant) {
             $when = getdate($participant['createdAt']);
             $currentDay = $when['year'] . '-' . $when['mon'] . '-' . $when['mday'];
             if (!$first && $lastDay != $currentDay) {
                 $this->updateStatsFor($projectId, $lastDay, $total);
                 $this->updateAreaStatsFor($projectId, $lastDay, $areas);
                 $lastDay = $currentDay;
             }
             if (!isset($areas[$participant['areaId']])) {
                 $areas[$participant['areaId']] = 0;
             }
             $total += $participant['peopleNum'];
             $areas[$participant['areaId']] += $participant['peopleNum'];
             if ($first) {
                 $first = false;
                 $lastDay = $currentDay;
             }
         }
     }
 }