select - MySQL Join on two rows -

i'd able rows "articles" table based on 2 "categories" i'm having trouble joins. here's tables like:

 `articles` (   `article_id` smallint(5) unsigned not null auto_increment,   `article_name` varchar(255) not null   primary key (`article_id`) ) 

 `article_categories` (   `article_id` smallint(5) unsigned not null,   `category_id` smallint(5) unsigned not null   unique key `article_category_id` (`article_id`,`category_id`),   key `article_id` (`article_id`),   key `category_id` (`category_id`) ) 

now i'd able articles in both categories 3 , 5 (or unlimited number of categories). thought this:

 select * articles inner join article_categories ac on ac.article_id = a.article_id (ac.category_id = 3 , ac.category_id = 5) 

just clarify don't want articles in either 3 or 5, both 3 , 5.

i'm thinking 1 of simple things i've somehow missed due tiredness or something.

either or literally have join every category want include e.g:

 select a.* articles inner join article_categories ac on ac.article_id = a.article_id inner join article_categories ac2 on ac2.article_id = a.article_id (ac2.category_id = 3 , ac.category_id = 5) 

but i'm sure there's simpler solution that.

try

select    articles.article_id    articles,    article_categories    articles.article_id=article_categories.article_id ,   article_categories.category_id in(3,5) group   article_categories.article_id having count(*)>=2;