问优化sql脚本

EN

With accounts As 
(
    select account_id, creation_date 
    from account 
    where program_distributor = 'brinks'
    and channel = 'online'
    and creation_year = 2017
),
Form_opens as 
(
    select session_id, log_time 
    from web_action_log 
    where web_action = 'open_dd_form'
),
Mapping as 
(
    select session_id, account_id 
    from web_link
)
Select
    trunc (acc.creation_date), 
    count(distinct acc.account_id), 
    count (distinct fo.account_id) 
from accounts acc 
left outer join mapping mp
    on acc.account_id = mp.account_id
Left outer join form_opens fo
    on mo.session_id = fo.session_id and 
    acc.creation_date > do.log_time
Group by trunc(acc.creation_date)
Order by 1;