WikiProject to pagecat counts, 10% scan, limit 2M rows, prefilter

SQL

SELECT
  pagecats.cl_to,
--  talkcats.cl_to,
  -- REGEXP_EXTRACT(talkcats.cl_to, '(?WikiProject_|.*_importance_|.*_priority_|Unassessed)(.*)'), -- does not work
  COUNT(*) AS my_count
FROM
  page AS article
  INNER JOIN page AS talk ON talk.page_title = article.page_title
  INNER JOIN categorylinks AS pagecats ON pagecats.cl_from = article.page_id
  INNER JOIN categorylinks AS talkcats ON talkcats.cl_from = talk.page_id
WHERE
  article.page_random < 0.5    -- page_random is between 0 and 1, so this sets the probe size
  AND article.page_namespace = 0
  AND talk.page_namespace = 1
  AND article.page_is_redirect = 0
  AND talk.page_is_redirect = 0
  -- filter out soft redirect and disambig pages entirely
  AND NOT EXISTS (SELECT 1 from page WHERE 
        pagecats.cl_to LIKE "%disambig%"
        OR pagecats.cl_to LIKE "%Disambig%"
        OR pagecats.cl_to LIKE "%redirect%"
        OR pagecats.cl_to LIKE "%Redirect%"
                 )
  AND (
        talkcats.cl_to LIKE "%WikiProject_%"
        OR talkcats.cl_to LIKE "%-Class_%_articles"
        OR talkcats.cl_to LIKE "%-importance_%_articles"
        OR talkcats.cl_to LIKE "%-priority_%_articles"
        OR talkcats.cl_to LIKE "Unassessed_%_articles"
      )  
  AND NOT (
            talkcats.cl_to LIKE "%vital%"
            OR talkcats.cl_to LIKE "%Version%"
  )
  AND NOT (pagecats.cl_to LIKE "%Disambig%" OR pagecats.cl_to LIKE "%disambig%" OR pagecats.cl_to LIKE "%set_index%" OR pagecats.cl_to LIKE "Set_index%")
  AND NOT (talkcats.cl_to LIKE "%Disambig%" OR talkcats.cl_to LIKE "%disambig%")
  AND NOT (pagecats.cl_to LIKE "Short_description%" 
           OR pagecats.cl_to LIKE "%_errors%"
           OR pagecats.cl_to LIKE "CS1_%"           
           OR pagecats.cl_to LIKE "%short_description%"
           OR pagecats.cl_to LIKE "%articles%"
           OR pagecats.cl_to LIKE "Articles%"
           OR pagecats.cl_to LIKE "%pages%"
           OR pagecats.cl_to LIKE "%disputes%"
           OR pagecats.cl_to LIKE "Pages_%"
           OR pagecats.cl_to LIKE "Use_dmy_date%"
           OR pagecats.cl_to LIKE "Use_mdy_date%"
           OR pagecats.cl_to LIKE "Use_%"
           OR pagecats.cl_to LIKE "EngvarB_%"
           OR pagecats.cl_to LIKE "%Wikipedia%"
           OR pagecats.cl_to LIKE "%articles%"
           OR pagecats.cl_to LIKE "%Articles%"
           OR pagecats.cl_to LIKE "%Wikidata%"
           OR pagecats.cl_to = "Source_attribution"
           OR pagecats.cl_to LIKE "Webarchive%")
GROUP BY  pagecats.cl_to
ORDER BY my_count DESC, pagecats.cl_to
LIMIT 2000000
SQL

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