with tmp as(select 
*,
row_number() over (partition by sessioN_id order by ex_timestamp) rn
from process_log)
,
tmp2 as
(select *,count() over (partition by session_id) cnt


from tmp
where tmp.rn= cast(substr(tmp.process_id,5,1) as integer)
), tmp3 as(
select *

from tmp2
where rn<=cnt
)
select process_id,count(session_id) CNT
from tmp3

group by process_id
order by 1