I figured this our. pasting this final query of mine just in case if it will help any one.
select to_char(cast(created as date),'YYYY-MM-DD') as Report_date,
count(distinct(case when event_type in ('Flash C Log') then user_id else 0 end)) as Flash_Log,
count(distinct(case when (event_type = 'Client C Log') then user_id else 0 end)) as Client_Log
from events e
where created between '25-SEP-16' and '27-SEP-16'
group by to_char(cast(created as date),'YYYY-MM-DD')
order by to_char(cast(created as date),'YYYY-MM-DD');