Missing primary articles (cswiki)

SQL

/*
SELECT P1.page_title AS first_title, P2.page_title AS second_title
FROM page AS P1, page AS P2
WHERE P1.page_namespace = 0
AND P1.page_title LIKE '%\_(%)'
AND P1.page_title NOT LIKE '%)%(%' AND P1.page_title NOT LIKE '%(%(%'
AND P2.page_namespace = 0 AND P2.page_title LIKE CONCAT(SUBSTRING_INDEX(P1.page_title, '_(', 1), '\_(%)')
AND P1.page_title < P2.page_title AND P1.page_is_redirect = 0 AND P2.page_is_redirect = 0
AND SUBSTRING_INDEX(P1.page_title, '_(', 1) = SUBSTRING_INDEX(P2.page_title, '_(', 1)
AND NOT EXISTS (
  SELECT 1 FROM page AS P3 WHERE P3.page_namespace = 0 AND P3.page_title = SUBSTRING_INDEX(P1.page_title, '_(', 1)
)
ORDER BY P1.page_title;
*/
SELECT P1.page_title AS first_title FROM page AS P1
WHERE P1.page_namespace = 0
AND P1.page_is_redirect = 0
AND P1.page_title LIKE '%\_(%)'
AND P1.page_title NOT LIKE '%)%(%'
AND P1.page_title NOT LIKE '%(%(%'
AND NOT EXISTS (
  SELECT 1 FROM page AS P2 WHERE P2.page_namespace = 0 AND P2.page_title = SUBSTRING_INDEX(P1.page_title, '_(', 1)
)
ORDER BY P1.page_title;
SQL

Checking query status...
