Selecting columns messes up order of rows - mysql

Question

I have 3 tables blog_articles, blog_tags and blog_articles_tags. Pretty basic stuff, a blog where articles can have tags.
CREATE TABLE `blog_articles` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`title` varchar(255) NOT NULL,
`body` text NOT NULL,
`datetime` datetime NOT NULL,
`author` int(10) unsigned DEFAULT NULL,
`published` tinyint(1) NOT NULL DEFAULT '0',
PRIMARY KEY (`id`),
KEY `author` (`author`),
FULLTEXT KEY `title` (`title`,`body`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
CREATE TABLE `blog_articles_tags` (
`article` int(10) unsigned NOT NULL,
`tag` int(10) unsigned NOT NULL,
PRIMARY KEY (`article`,`tag`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `blog_tags` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` varchar(255) DEFAULT NULL,
`description` text,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
Here is a working example, selecting blog posts with their tags and author
But if I switch the sort from descending to ascending, I get messed up results
However if I remove the columns of the blog_tags table from the list of columns to select, the order is correct
There are two questions I would like to ask:
Why is the sequence of the rows altered by the columns that are selected?
How can I prevent this without modifying the SQL statement anywhere outside of the inner-most query?
I cannot modify the SQL statement because that is an automatically generated statement and I can not determine (easily if at all) what the sort will be and if any successive columns added to the select clause will alter the results even further.

Answer 1

Queries in SQL are unordered unless you specify an ORDER BY. Any ordering you happen to get is an artifact of the implementation and cannot be relied upon.
You have an ORDER BY in one of your virtual tables, but nothing for the outer query. Since it includes several joins you can't even count on MySQL coincidentally preserving the order of the virtual table.
There's little reason to put an ORDER BY on a sub-query unless you're doing something advanced like adding a row-number. So the whole sub-query can be dropped and just join on blog_articles. Then you can ORDER BY blog_articles.id.