with step as(
select
    session_id
    ,process_id
    ,ex_timestamp
    ,rank()over(partition by session_id order by ex_timestamp) as r
from process_log
)
,ridatsu_step as(
select
    session_id
    ,min(r) as minr
from step
   where cast(substr(process_id,-1) as int) != r
group by session_id
)

select
    process_id as PROCESS
    ,count(
        distinct case when (cast(substr(step.process_id,-1) as int) < ridatsu_step.minr or ridatsu_step.minr is null)
            then step.session_id
        end
    ) as CNT
from step
left outer join ridatsu_step
on step.session_id=ridatsu_step.session_id
group by process_id
order by process_id