滑动窗口

   
   


    
    
HOP(<time-attr>, <slide-interval>, <size-interval>)

    
    
<slide-interval>: INTERVAL 'string' timeUnit

    
    
<size-interval>: INTERVAL 'string' timeUnit
   
   

   
   


    
    
CREATE TABLE user_clicks(

    
    
  username varchar,

    
    
  click_url varchar,

    
    
  ts timeStamp,

    
    
  WATERMARK wk FOR ts as withOffset(ts, 2000)  -- 为 rowtime 定义watermark

    
    
) with (

    
    
  type='datahub',

    
    
  ...

    
    
);

    
    


    
    
CREATE TABLE tumble_output(

    
    
  window_start TIMESTAMP,

    
    
  window_end TIMESTAMP,

    
    
  username VARCHAR,

    
    
  clicks BIGINT

    
    
) with (

    
    
  type='rds'

    
    
);

    
    


    
    
INSERT INTO tumble_output

    
    
SELECT 

    
    
  HOP_START(ts, INTERVAL '30' SECOND, INTERVAL '1' MINUTE),

    
    
  HOP_END(ts, INTERVAL '30' SECOND, INTERVAL '1' MINUTE),

    
    
  username, 

    
    
  COUNT(click_url)

    
    
FROM window_input

    
    
GROUP BY HOP(ts, INTERVAL '30' SECOND, INTERVAL '1' MINUTE), username