Block history of users with 5000+ edits, filter by original reason

SQL

SELECT * -- this outer query is solely so we can refer to the ugly case in subquery2 by name
FROM (SELECT *,
             CASE
               WHEN log_action = 'block' or log_title != LAG(log_title, 1) OVER (ORDER BY log_title ASC, log_timestamp ASC)
                 THEN comment_text
               ELSE LAG(comment_text, 1) OVER (ORDER BY log_title ASC, log_timestamp ASC)
             END AS original_reason
      FROM (SELECT log_timestamp, log_id, log_action, actor_name, REPLACE(log_title, '_', ' ') AS log_title, user_editcount, comment_text, log_params
            FROM logging
            JOIN user ON user_name = REPLACE(log_title, '_', ' ')
            JOIN actor_logging ON log_actor = actor_id
            JOIN comment_logging ON log_comment_id = comment_id
            WHERE log_type = 'block'
              AND user_editcount <= 1000 AND user_editcount > 100

            UNION

            SELECT '99999999999999', NULL, 'currently blocked', NULL, user_name, user_editcount, NULL, NULL
            FROM ipblocks_ipindex
            JOIN user ON user_id = ipb_user
            WHERE user_editcount <= 1000 AND user_editcount > 100

            ORDER BY log_title ASC, log_timestamp ASC
           ) subquery1
     ) subquery2
WHERE original_reason REGEXP '(?i)(attack|harass|racis|civil|sexis|bigot|WP:(NO?)?PA|insult|slur|stereotyp|bully|gravedanc|aspersion|WP:HA|hound|following|outing|dox|off-?wiki|personali[sz])'
ORDER BY log_title ASC, log_timestamp ASC;
SQL

Checking query status...
