Apache kafka ksqlDB中通过翻滚窗口生成零计数的可能方法

对于滚动窗口查询，如

CREATE TABLE rating_count
    WITH (kafka_topic='rating_count') AS
    SELECT title,
           COUNT(*) AS rating_count,
           TIMESTAMPTOSTRING(window_start, 'yyy-MM-dd HH:mm:ss', 'UTC') as window_start,
           TIMESTAMPTOSTRING(window_end, 'yyy-MM-dd HH:mm:ss', 'UTC') as window_end
    FROM ratings
    WINDOW TUMBLING (SIZE 1 HOURS)
    GROUP BY title
    EMIT FINAL;

如果窗口边界内没有接收到的组的记录，是否有任何方法为某些组（此处的标题）生成零计数

换句话说，我想知道是否可以在每次触发窗口聚合时为固定数量的组生成计数。比如说

+--------------------+--------------------+--------------------+--------------------+
|TITLE               |RATING_COUNT        |WINDOW_START        |WINDOW_END          |
+--------------------+--------------------+--------------------+--------------------+
|Die Hard            |0                   |2019-07-09 00:00:00 |2019-07-09 01:00:00 |
|Tree of Life        |2                   |2019-07-09 00:00:00 |2019-07-09 01:00:00 |
|A Walk in the Clouds|1                   |2019-07-09 00:00:00 |2019-07-09 01:00:00 |
|Die Hard            |1                   |2019-07-09 01:00:00 |2019-07-09 02:00:00 |
|Tree of Life        |0                   |2019-07-09 01:00:00 |2019-07-09 02:00:00 |
|A Walk in the Clouds|2                   |2019-07-09 01:00:00 |2019-07-09 02:00:00 |
|Die Hard            |1                   |2019-07-09 02:00:00 |2019-07-09 03:00:00 |
|Tree of Life        |2                   |2019-07-09 02:00:00 |2019-07-09 03:00:00 |
|A Walk in the Clouds|0                   |2019-07-09 02:00:00 |2019-07-09 03:00:00 |
+-----------------------------------------------------------------------------------+