WINDOW UNIQUE
This window is used with a namespace such as WINDOW UNIQUE:WINDOW_NAME. The window retains and processes unique events based on the given parameters.
Unique Windows
| Function | Description |
|---|---|
| EVER | Retains latest events based on the unique keys. |
| TUMBLING_EXTERNAL_TIME | Tumbling time window holds the latest events based on unique.key and various parameters for time. |
| FIRST | Retain first set of unique events based on unique.key. |
| TUMBLING_FIRST | Tumbling window holds window.length unique events based on unique.key. |
| TUMBLING_FIRST_TIME | A batch-time or tumbling window that holds the unique events based on unique.key and sliding time period window.time with time offset defined by parameter start.time. |
| SLIDING_LENGTH | A sliding length window that holds the latest unique events base in unique.key. |
| TUMBLING_LENGTH | This is a batch (tumbling) window that holds window.length number of latest unique events. |
| SLIDING_TIME | This is a sliding time window that holds the latest unique events that arrived during window.time. |
| TUMBLING_TIME | This is a batch (tumbling) time window that is updated with the latest events based on unique.key tumbling time period window.time and time offset start.time. |
| TUMBLING_TIME_LENGTH | The window tumbles upon the elapse of the time window window.time, or when a number of unique events have arrived i.e. window.length. |
Example 1
CREATE STREAM DriverChangeStream (trainID STRING, driver STRING);
INSERT expired events INTO PreviousDriverChangeStream
SELECT trainID, driver
FROM DriverChangeStream WINDOW UNIQUE:EVER(trainID);