newbie retention using thanks

SQL

use itwiki_p;

select count(A.user_id)

from (select user_id, user_name
	from user
    where (
      user_registration < timestamp('2018-01-08')
      and user_registration >= timestamp('2018-01-01'))) as A
    
join (select rev_user, rev_user_text
    from revision
    where (
        rev_timestamp < timestamp('2018-02-01') 
        and rev_timestamp >= timestamp('2018-01-01') 
        and rev_user != 0)
    group by rev_user) as B

on A.user_id = B.rev_user

left join (select log_title
          from logging_userindex
      	  where (
      		  log_action = 'thank' and log_type='thanks'
		      and log_timestamp < timestamp('2018-02-01')
              and log_timestamp >= timestamp('2018-01-01'))
      	  group by log_title) as C 

on A.user_name = C.log_title
or B.rev_user_text = C.log_title
where (C.log_title is null);

#join (select rev_user
#    from revision
#    where (
#        rev_timestamp < timestamp('2018-07-01') 
#        and rev_timestamp >= timestamp('2018-04-01') 
#        and rev_user != 0)
#    group by rev_user) as D

#on A.user_id = D.rev_user;
SQL

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