SELECT 
   Articles.article_id, 
   COUNT( Categories.article_id ) AS total 
FROM CategoryArticles 
LEFT JOIN Articles USING (article_id)
WHERE 
   CategoryArticles.category_id IN (1,2,3)
GROUP BY CategoryArticles.article_id
HAVING  total = 3

我为表使用了一些不同的名称，因为在您的示例中，很难注意到category和categories之间的区别.

I used a bit different names for table because in your example the distinction between category and categories is hard to notice.