CRON()

This window outputs the arriving events as and when they arrive and resets (expires) the window periodically based on the given cron expression.

Syntax

WINDOW CRON(<STRING> expression)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
expression	The cron expression that resets the window.		STRING	No	No

Example 1

CREATE STREAM InputEventStream (symbol string, price float, volume int);
CREATE SINK STREAM OutputStream (symbol string, totalPrice double);

@info(name = 'query1')
INSERT INTO OutputStream
SELECT symbol, sum(price) AS totalPrice
FROM InputEventStream WINDOW CRON('*/5 * * * * ?');

This lets the totalPrice gradually increase and resets to zero as a batch every five seconds.

Example 2

CREATE STREAM StockEventStream (symbol string, price float, volume int);
CREATE WINDOW StockEventWindow (symbol string, price float, volume int) CRON('*/5 * * * * ?');
CREATE SINK STREAM OutputStream (symbol string, totalPrice double);

@info(name = 'query0')
INSERT INTO StockEventWindow
FROM StockEventStream;

@info(name = 'query1')
INSERT INTO OutputStream 
SELECT symbol, sum(price) AS totalPrice
FROM StockEventWindow;

The defined window enables the totalPrice to gradually increase and resets to zero as a batch every five seconds.