PHP completes missing dates in date ranges/returns missing dates

query("SELECT id, date FROM `table_name` WHERE `areaname` = 'xxx'");while ($r = $db->fetch_array($result)) {$list[] = $r['date'];$lists[] = $r;}# complete date$newData = spd('2012-01-01', '2013-08-08');# missing date$difference_set_arr = array_diff($newData, $list);echo '
';var_dump("'" . implode("','", $difference_set_arr) . "'");die;function spd($minimum_time, $maximum_time){# Date must use string type because date is not a numeric type$collection = [];// loop calculation$minimum_time = strtotime($minimum_time);$maximum_time = strtotime($maximum_time);while ($minimum_time <= $maximum_time) {$collection[] += $minimum_time;$minimum_time = strtotime('+1 day', $minimum_time);}foreach ($collection as &$value) {$value = date('Y-m-d', $value);}return $collection;}