I'm using a 2 table tagging system for articles (myisam) and I'm trying to get related articles based on the tags and category_id of the article currently being viewed.

What would be the optimal query to achieve this? I only seem to be able to find answers for 3 table tag systems.

`article_id` int(11) NOT NULL DEFAULT '0',
`tag` varchar(99) NOT NULL DEFAULT '',
  PRIMARY KEY (`article_id`,`tag`),
  KEY `tag_ix` (`tag`)
`article_id` int(11) NOT NULL AUTO_INCREMENT,
`title` varchar(255) NOT NULL DEFAULT '',
`content` text NOT NULL,
`category_id` int(11) NOT NULL,
`tags` varchar(255) NOT NULL DEFAULT '',
PRIMARY KEY (`article_id`), 
KEY `category_id` (`category_id`)
Thanks for any help.