Essayez ceci :
SELECT *
FROM tablename
WHERE keywordId IN (1, 12)
GROUP BY articleId
HAVING COUNT(*) = 2;
Consultez la SQL FIDDLE DEMO
Essayez ceci :
SELECT *
FROM tablename
WHERE keywordId IN (1, 12)
GROUP BY articleId
HAVING COUNT(*) = 2;
Consultez la SQL FIDDLE DEMO