Incubator, 2 or fewer avg monthly editors since 2019

SQL

WITH base_table AS (
  SELECT DISTINCT 
  	rev_id, rev_actor, rev_timestamp, rev_len, rev_parent_id,
  	page_namespace, page_id, actor_id,
  	REGEXP_SUBSTR(page_title, 'W[a-z]/[a-z]+') AS prefix,
  	rc_new_len - rc_old_len AS byte_diff
  FROM revision rev
  JOIN page ON rev.rev_page = page.page_id
  JOIN actor ON rev.rev_actor = actor.actor_id
  LEFT OUTER JOIN recentchanges rc ON rev.rev_id = rc.rc_this_oldid
  WHERE page_namespace IN (0, 1, 10, 11, 14, 15, 828, 829)
  HAVING prefix <> ''
  ORDER BY rev_id DESC),
  
  edits_table AS (
  SELECT prefix, COUNT(DISTINCT rev_id) AS edit_count
  FROM base_table
  GROUP BY prefix),

  actor_table AS (
  SELECT prefix, COUNT(DISTINCT actor_id) AS actor_count
  FROM base_table
  GROUP BY prefix),

  page_table AS (
  SELECT prefix, COUNT(DISTINCT page_id) AS pages_count
  FROM base_table
  GROUP BY prefix),
  
  last_2Y AS (
    SELECT *, YEAR(rev_timestamp) AS year, MONTH(rev_timestamp) AS month
    FROM base_table
    WHERE MONTH(rev_timestamp) >= MONTH(NOW()) - 24
    AND MONTH(rev_timestamp) < MONTH(NOW())
  AND YEAR(rev_timestamp) = YEAR(NOW())),
  
  monthly_grouping AS (
    SELECT prefix, month, 
    	COUNT(DISTINCT rev_id) AS edits_by_month,
    	COUNT(DISTINCT actor_id) AS editors_by_month
    FROM last_2Y
    GROUP BY prefix, month),
    
  avg_table AS (
    SELECT prefix, 
    	AVG(edits_by_month) AS avg_edits_2Y, 
    	AVG(editors_by_month) AS avg_editors_2Y
    FROM monthly_grouping
    GROUP BY prefix)

SELECT e.prefix, edit_count, actor_count,  
CAST(avg_edits_2Y AS INT) AS avg_edits_2Y, CAST(avg_editors_2Y AS INT) AS avg_editors_2Y
FROM edits_table e
JOIN actor_table a ON a.prefix = e.prefix
JOIN avg_table ON avg_table.prefix = e.prefix
ORDER BY avg_table.avg_editors_2Y DESC
SQL

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