Never used a UNION or a JOIN, but I need to

[jlipin3]

I'm using WordPress.  I want to select a group of id's in one table, and use those id's to select a bunch of posts in another table, and only retrieve the most recent post.

 

So, theoretically, I want to do this:

 

$article_ids_query = mysql_query("SELECT `object_id` FROM `wp_term_relationships` WHERE `term_taxonomy_id`='" . $term_taxonomy_id[0] . "'"); //this will retrieve a bunch of `object_id's`

 

$articles = mysql_query("SELECT `post_title`, `post_content` FROM `wp_posts` WHERE `ID`='" . $article_ids_query . "'");

 

 

The obvious problem is that the $article_ids_query is going to be a result set.

 

How could I do it so that I use the query in $article_ids_query to be part of the $articles query.

 

This is what I could come up with using a "UNION", but I've never used UNION before:

 

(SELECT `object_id` as `a` FROM `wp_term_relationships` WHERE `term_taxonomy_id`='" . $term_taxonomy_id[0] . "') UNION (SELECT `post_content`, `post_title` FROM `wp_posts` WHERE `ID`=`a` AND `post_type`='post') LIMIT 1 ORDER BY `post_date` ASC

 

The help is obviously hugely appreciated, freaks.  Josh

[fenway]

Actually, you just want a join here:

 

$articles = mysql_query("SELECT `post_title`, `post_content` FROM `wp_posts` JOIN `wp_term_relationships`ON ( `wp_term_relationships`.`object_id` = `wp_posts`.`ID` ) WHERE `term_taxonomy_id`='" . $term_taxonomy_id[0] . "'");