Это было тихо сложно сделать :). Я попытался фрагментировать подзапросы для хорошей читабельности. Вероятно, это не очень эффективный способ делать то, что вы хотите, но он выполняет свою работу.
-- collect all days to make sure there are no missing days
WITH all_days_cte(dt) as (
SELECT
generate_series(
(SELECT min(date_trunc('day', log_time)) from your_table),
(SELECT max(date_trunc('day', log_time)) from your_table),
'1 day'
)::DATE
),
-- collect all useres
all_users_cte as (
select distinct
user_id
from your_table
),
-- setup the table with infos needed, i.e. only the last status by day and user_id
infos_to_aggregate_cte as (
select
s.user_id,
s.dt,
s.status
from (
select
user_id,
date_trunc('day', log_time)::DATE as dt,
status,
row_number() over (partition by user_id, date_trunc('day', log_time) order by log_time desc) rn
from your_table
where status is not null
) s
-- only the last status of the day
where s.rn = 1
),
-- now we still have a problem, we need to find the last status, if there was no change on a day
completed_infos_cte as (
select
u.user_id,
d.dt,
-- not very efficient, but found no other way (first_value(...) would be nice, but there is no simple way to exclude nulls
(select
status
from infos_to_aggregate_cte i2
where i2.user_id = u.user_id
and i2.dt <= d.dt
and i2.status is not null
order by i2.dt desc
limit 1) status
from all_days_cte d
-- cross product for all dates and users (that is what we need for our aggregation)
cross join all_users_cte u
left outer join infos_to_aggregate_cte i on u.user_id = i.user_id
and d.dt = i.dt
)
select
c.dt,
sum(case when status = 'A' then 1 else 0 end) status_a,
sum(case when status = 'B' then 1 else 0 end) status_b,
sum(case when status = 'C' then 1 else 0 end) status_c
from completed_infos_cte c
group by c.dt
order by c.dt desc