ThinkPHP搜索7天15天30天数据where语句

$pending_times = [
            // 7天
            1 => [['pend', '=', strtotime(date('Y-m-d 23:59:59', time()))]],
            // 15天
            2 => [['pend', '=', strtotime(date('Y-m-d 23:59:59', time()))]],
            // 30
            3 => [['pend', '=', strtotime(date('Y-m-d 23:59:59', time()))]],
            // 90
            4 => [['pend', '=', strtotime(date('Y-m-d 23:59:59', time()))]],
        ];
        if ($pending) {
            // 根据前端的索引搜索
            $where[] = $pending_times[$pending];
        }