in 转 join on
select article.* from article WHERE article.article_id IN (
SELECT article_category_ref.article_id FROM article_category_ref
WHERE article_category_ref.category_id = 10
)
----》》
select article.* from article join(
SELECT * FROM article_category_ref
)t1 on article.article_id = t1.article_id and t1.category_id=10