How to find the time and step between status change - sql

Question

I'm trying to query a dataset about user status changes. and I want to find out the time it takes for the status to change, and the steps in between(number of rows).
Example data:
user_id
Status
date
1
a
2001-01-01
1
a
2001-01-08
1
b
2001-01-15
1
b
2001-01-28
1
a
2001-01-31
1
b
2001-02-01
2
a
2001-01-08
2
a
2001-01-18
2
a
2001-01-28
3
b
2001-03-08
3
b
2001-03-18
3
b
2001-03-19
3
a
2001-03-20
Desired output:
user_id
From
to
days in between
Steps in between
1
a
b
14
2
1
b
a
16
2
1
a
b
1
1
3
b
a
12
3

Answer 1

You might consider below another approach.
WITH partitions AS (
SELECT *, COUNTIF(flag) OVER w AS part FROM (
SELECT *, ROW_NUMBER() OVER w AS rn, status <> LAG(status) OVER w AS flag,
FROM sample_data
WINDOW w AS (PARTITION BY user_id ORDER BY date)
) WINDOW w AS (PARTITION BY user_id ORDER BY date)
)
SELECT user_id,
LAG(ANY_VALUE(status)) OVER w AS `from`,
ANY_VALUE(status) AS `to`,
EXTRACT(DAY FROM MIN(date) - LAG(MIN(date)) OVER w) AS days_in_between,
MIN(rn) - LAG(MIN(rn)) OVER w AS steps_in_between
FROM partitions
GROUP BY user_id, part
QUALIFY `from` IS NOT NULL
WINDOW w AS (PARTITION BY user_id ORDER BY MIN(date));
Query results

Answer 2

with main as (
select
*,
dense_rank() over(partition by user_id order by date) as rank_,
row_number() over(partition by user_id, status order by date) as rank_2,
row_number() over(partition by user_id, status order by date) - dense_rank() over(partition by id order by date) as diff,
row_number() over(partition by user_id order by date) as row_num,
lag(status) over(partition by user_id order by date) as prev_status,
concat(lag(status) over(partition by user_id order by date) , ' to ' , status) as status_change
from table
),
new_rank as (
select
*,
rown_num - diff as row_num_diff,
min(date) over(partition by user_id, status, rown_num - diff) as min_date
from main
),
prev_date as (
select
*,
lag(min_date) over(partition by user_id order by date) as prev_min_date
from new_rank
)
select
status as from,
prev_status as to,
date_diff(prev_min_date, min_date, DAY) as days_in_between
from prev_date
where status !=prev_status and prev_status is not null
Does this seem to work? I tried to solve this but it's very hard to solve it without a fiddle plus:
you may remove the extra steps/ranks that I have added, I left them there so you can visually see what they are doing
I don't get your steps logic so it is missing from the code