New users' thanks

SQL

use kowiki_p;

select A.user_name, A.user_editcount
from 

	(select user_id, user_name, user_registration, user_editcount
    from user
	where
		(user_registration < timestamp('2018-04-01')
    	and
    	user_registration >= timestamp('2018-03-01')
    	and
        user_editcount > 0)) as A
        
    #left join
    #join
    #(select rev_user_text, rev_timestamp
    #	from revision
    #    where
    #	(rev_timestamp < timestamp('2018-06-01') and rev_timestamp >= timestamp('2018-05-01'))
    #	group by rev_user_text) as B
        
    #on A.user_name = B.rev_user_text
    #where (B.rev_user_text is null)
    order by A.user_editcount;
SQL

Checking query status...
