test #2 - Quarry

SQL

SELECT
	#source.page_title AS title_source,
   	#cl.cl_to AS prio_source
    target.page_title AS title_target,
    SUM(CASE WHEN cl.cl_to = 'Top-priority_mathematics_articles' THEN 1 ELSE 0 END) AS count_top,
    SUM(CASE WHEN cl.cl_to = 'High-priority_mathematics_articles' THEN 1 ELSE 0 END) AS count_high,
    SUM(CASE WHEN cl.cl_to = 'Mid-priority_mathematics_articles' THEN 1 ELSE 0 END) AS count_mid,
    SUM(CASE WHEN cl.cl_to = 'Low-priority_mathematics_articles' THEN 1 ELSE 0 END) AS count_low,
    SUM(CASE WHEN cl.cl_to = 'NA-priority_mathematics_articles'
        	   OR cl.cl_to = 'Unknown-priority_mathematics_articles' THEN 1 ELSE 0 END) AS count_na
FROM
	# hubungan antar artikel
	page AS source
    INNER JOIN pagelinks AS pl ON source.page_title = pl.pl_from
    INNER JOIN linktarget AS lt ON pl.pl_target_id = lt.lt_id
    INNER JOIN page AS target ON lt.lt_title = target.page_title

    # source harus punya talk page dengan category ...
    INNER JOIN page AS talk ON source.page_title = talk.page_title
	INNER JOIN categorylinks AS cl ON talk.page_id = cl.cl_from

    # target harus punya talk page dengan category ...    
    INNER JOIN page AS talk2 ON target.page_title = talk2.page_title
	INNER JOIN categorylinks AS cl2 ON talk2.page_id = cl2.cl_from

WHERE
	# source ada di main dan bukan redirect
	source.page_namespace = 0
	AND source.page_is_redirect = 0
	
	# target ada di main dan bukan redirect
    AND target.page_namespace = 0
    AND target.page_is_redirect = 0
    
    # talk ada di talk :D
    AND talk.page_namespace = 1
    AND talk2.page_namespace = 1
	
    # source dan target harus bertopik matematika
    AND cl.cl_to IN (
	  'Top-priority_mathematics_articles',
	  'High-priority_mathematics_articles',
	  'Mid-priority_mathematics_articles',
	  'Low-priority_mathematics_articles',
	  'NA-priority_mathematics_articles',
      'Unknown-priority_mathematics_articles')
  	AND cl2.cl_to IN (
	  'Top-priority_mathematics_articles',
	  'High-priority_mathematics_articles',
	  'Mid-priority_mathematics_articles',
	  'Low-priority_mathematics_articles',
	  'NA-priority_mathematics_articles',
      'Unknown-priority_mathematics_articles')
      
   GROUP BY title_target
SQL

Checking query status...
