session_window

session_window 介绍

session_window(time_column, gap_duration) - 根据指定的时间戳列和间隔持续时间生成会话窗口。有关详细解释和示例，请参见结构化流指南文档中的“时间窗口的类型”。

参数：

time_column - 用作按时间窗口化的时间戳的列或表达式。时间列必须是TimestampType类型。
gap_duration - 一个字符串，指定会话的超时时间，表示为“间隔值”（有关更多详细信息，请参见间隔文字。）对于固定间隔持续时间，或是一个应用于每个输入并计算为动态间隔持续时间的“间隔值”的表达式。

Examples:

> SELECT a, session_window.start, session_window.end, count(*) as cnt FROM VALUES ('A1', '2021-01-01 00:00:00'), ('A1', '2021-01-01 00:04:30'), ('A1', '2021-01-01 00:10:00'), ('A2', '2021-01-01 00:01:00') AS tab(a, b) GROUP by a, session_window(b, '5 minutes') ORDER BY a, start;
  A1    2021-01-01 00:00:00 2021-01-01 00:09:30 2
  A1    2021-01-01 00:10:00 2021-01-01 00:15:00 1
  A2    2021-01-01 00:01:00 2021-01-01 00:06:00 1
> SELECT a, session_window.start, session_window.end, count(*) as cnt FROM VALUES ('A1', '2021-01-01 00:00:00'), ('A1', '2021-01-01 00:04:30'), ('A1', '2021-01-01 00:10:00'), ('A2', '2021-01-01 00:01:00'), ('A2', '2021-01-01 00:04:30') AS tab(a, b) GROUP by a, session_window(b, CASE WHEN a = 'A1' THEN '5 minutes' WHEN a = 'A2' THEN '1 minute' ELSE '10 minutes' END) ORDER BY a, start;
  A1    2021-01-01 00:00:00 2021-01-01 00:09:30 2
  A1    2021-01-01 00:10:00 2021-01-01 00:15:00 1
  A2    2021-01-01 00:01:00 2021-01-01 00:02:00 1
  A2    2021-01-01 00:04:30 2021-01-01 00:05:30 1

Since: 3.2.0

sequence sha