How can I display posts from the other sites in a WordPress multisite setup?

Question

I have a small network of sites setup with WordPress 3.0's multisite feature. I would like to create another site which pulls certain posts from the various other sites to display. This new 'hub' site would seem like its own separate site to the user (with domain mapping), but its content is coming from the posts from the other sites.

How can I get posts from another site in a WordPress multisite setup? Can I query for posts based on the name of the site? The end result needs to be a collection of posts from the different sites sorted by date.

Thanks for your help.

Answer 1

This wouldn't be terribly difficult to set up with direct database calls. You can query posts from any site on the install with the $wpdb object. See Displaying Posts Using a Custom Select Query for information on using a custom database query, but keep in mind that instead of selecting from $wpdb->posts you're going to need to access the specific site table you want posts from. On a default Wordpress 3 install, this would be wp_12_posts where 12 is the site id. The id can be found in the wp_blogs table, or by looking at the ID column in the Sites section of the admin menu.