Time since first edit until being granted patroller right

SQL

use fawiki_p;
select log_title, first_edit_date, access_granted, datediff(access_granted, first_edit_date) as diff from
(
select log_title,
str_to_date(left(first_edit, 8), '%Y%m%d') first_edit_date,
str_to_date(left(min(log_timestamp), 8), '%Y%m%d') as access_granted from
(
select log_title, log_params, log_timestamp, first_edit
from logging
join (select rev_user_text, min(rev_timestamp) as first_edit from revision group by rev_user_text) f
on rev_user_text = log_title
join user
on log_title = user_name
join user_groups
on ug_user = user_id
and ug_group = 'patroller'
where log_type = 'rights' and log_action = 'rights' and log_params like '%patroller%'
) t1
group by log_title, first_edit
) t2
where first_edit_date > '2013-01-01'
order by 4;

SQL

Checking query status...