16.20 - nPath Filters Example - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ - NewSQL Engine Analytic Functions

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
July 2019
Content Type
Programming Reference
Publication ID
B035-1206-162K
Language
English (United States)

Using clickstream data from an online store, this example finds the sessions where the user visited the checkout page within 10 minutes of visiting the home page. Because there is no way to know in advance how many rows might appear between the home page and the checkout page, the example cannot use a LAG or LEAD expression. Therefore, it uses the Filter syntax element.

Input

clickstream
userid sessionid clicktime pagetype
1 1 10-10-2012 10:15 home
1 1 10-10-2012 10:16 view
1 1 10-10-2012 10:17 view
1 1 10-10-2012 10:20 checkout
1 1 10-10-2012 10:30 checkout
1 1 10-10-2012 10:35 view
1 1 10-10-2012 10:45 view
2 2 10-10-2012 13:15 home
2 2 10-10-2012 13:16 view
2 2 10-10-2012 13:43 checkout
2 2 10-10-2012 13:35 view
2 2 10-10-2012 13:45 view

SQL Call

SELECT * FROM Npath (
  ON clickstream PARTITION BY userid ORDER BY clicktime
  USING
  Symbols (
    pagetype='home' AS home,
    pagetype <> 'home' AND pagetype <> 'checkout' AS clickview,
    pagetype='checkout' AS checkout
  )
  Pattern ('home.clickview*.checkout')
  Result (
    FIRST(userid of ANY(home, checkout, clickview)) AS userid,
    FIRST (sessionid of ANY(home, checkout, clickview)) AS sessioinid,
    COUNT (* of any(home, checkout, clickview)) AS cnt,
    FIRST (clicktime of ANY(home)) AS firsthome,
    LAST (clicktime of ANY(checkout)) AS lastcheckout
  )
  Filter (
      FIRST (clicktime + interval '10' minute  OF ANY (home)) >
        FIRST (clicktime of any(checkout))
  )
  Mode (NONOVERLAPPING)
);

Output

userid sessionid cnt firsthome lastcheckout
1 1 4 2012-10-10 10:15:00 2012-10-10 10:20:00