全部面试刷题微服务数据库消息队列搜索引擎大数据运维 go语言人工智能

Flink SQL支持哪些窗口函数？

提问者：帅平问题分类：面试刷题

Flink SQL支持哪些窗口函数？

Flink面试题 Flink FlinkSql

发布于：2个月前 (05-16) IP属地：

2 个回答

忆雪

支持的窗口函数有：
1、滚动窗口：固定大小，不重叠的时间窗口

SELECT 
    TUMBLE_START(ts, INTERVAL '1' HOUR) AS window_start,
    TUMBLE_END(ts, INTERVAL '1' HOUR) AS window_end,
    SUM(amount) AS total
FROM orders
GROUP BY TUMBLE(ts, INTERVAL '1' HOUR);

2、滑动窗口：固定大小且按步长滑动的窗口，窗口间可重叠

SELECT 
    HOP_START(ts, INTERVAL '5' MINUTE, INTERVAL '1' HOUR) AS window_start,
    SUM(amount) AS total
FROM orders
GROUP BY HOP(ts, INTERVAL '5' MINUTE, INTERVAL '1' HOUR);

发布于：2个月前 (05-16) IP属地：

对的时间对的人

3、会话窗口：通过不活动间隙切分数据，动态窗口大小

SELECT 
    SESSION_START(ts, INTERVAL '10' MINUTE) AS window_start,
    COUNT(user_id) AS visits
FROM user_clicks
GROUP BY SESSION(ts, INTERVAL '10' MINUTE);

4、累积窗口：再固定窗口内份阶段输出结果

SELECT 
    CUMULATE_START(ts, INTERVAL '1' HOUR, INTERVAL '10' MINUTE) AS window_start,
    SUM(amount) AS partial_total
FROM orders
GROUP BY CUMULATE(ts, INTERVAL '1' HOUR, INTERVAL '10' MINUTE);

发布于：2个月前 (05-16) IP属地：

我来回答