User Life Cycle SQL Query Logic in Snowflake - sql

Question

I am working on building a query to track the life cycle of an user through the platform via events. The table EVENTS has 3 columns USER_ID, DATE_TIME and EVENT_NAME. Below is a snapshot of the table,
My query should return the below result (the first timestamp for the registered event followed by the immediate/next timestamp of the following log_in event and finally followed by the immediate/next timestamp of the final landing_page event),
Below is my query ,
WITH FIRST_STEP AS
(SELECT
USER_ID,
MIN(CASE WHEN EVENT_NAME = 'registered' THEN DATE_TIME ELSE NULL END) AS REGISTERED_TIMESTAMP
FROM EVENTS
GROUP BY 1
),
SECOND_STEP AS
(SELECT * FROM EVENTS
WHERE EVENT_NAME = 'log_in'
ORDER BY DATE_TIME
),
THIRD_STEP AS
(SELECT * FROM EVENTS
WHERE EVENT_NAME = 'landing_page'
ORDER BY DATE_TIME
)
SELECT
a.USER_ID,
a.REGISTERED_TIMESTAMP,
(SELECT
CASE WHEN b.DATE_TIME >= a.REGISTRATIONS_TIMESTAMP THEN b.DATE_TIME END AS LOG_IN_TIMESTAMP
FROM SECOND_STEP
LIMIT 1
),
(SELECT
CASE WHEN c.DATE_TIME >= LOG_IN_TIMESTAMP THEN c.DATE_TIME END AS LANDING_PAGE_TIMESTAMP
FROM THIRD_STEP
LIMIT 1
)
FROM FIRST_STEP AS a
LEFT JOIN SECOND_STEP AS b ON a.USER_ID = b.USER_ID
LEFT JOIN THIRD_STEP AS c ON b.USER_ID = c.USER_ID;
Unfortunately I am getting the "SQL compilation error: Unsupported subquery type cannot be evaluated" error when I try to run the query

Answer 1

This is a perfect use case for MATCH_RECOGNIZE.
The pattern you are looking for is register anything* login anything* landing and the measures are the min(iff(event_name='x', date_time, null)) for each.
Check:
https://towardsdatascience.com/funnel-analytics-with-sql-match-recognize-on-snowflake-8bd576d9b7b1
https://docs.snowflake.com/en/user-guide/match-recognize-introduction.html
Set the output to one row per match.
Untested sample query:
select *
from data
match_recognize(
partition by user_id
order by date_time
measures min(iff(event_name='register', date_time, null)) as t1
, min(iff(event_name='log_in', date_time, null)) as t2
, min(iff(event_name='landing_page', date_time, null)) as t3
one row per match
pattern(register anything* login anything* landing)
define
register as event_name = 'register'
, login as event_name = 'log_in'
, landing as event_name = 'landing_page'
);