Is there a full explanation on how to share a database with two Wordpress sites on same server?

Question

I have read that you can have two wordpress database tables (using different table prefixes) to share the same database.

I understand the concept but does any know of or can anyone provide an outline on the processes involved when using search for example. I would ideally, like to search from one site and be able to get results from both sites (_wp1 posts and _wp2 posts). How would I set this up?

Current setup:

Site one: Free site blog content, 5000 + posts, big database. Search will only return free content (_wp1)

Site two: (new) A premium paid content subscription service featuring new blogs. Search will return new premium content (_wp2) AND the original free content. So is it best to write all posts from the free site and just set whether its premium, or should I separate where the blogs are written? Custom field filters need to work with this (assuming the posts have the same post setup on both).

Thanks

Answer 1

It is possible to add custom queries to the 2nd site, and pull posts from the first site:

<?php
$mydb = new wpdb('root','root','dev1','localhost');
$query_result = $mydb->get_results("SELECT * FROM $wpdb->posts WHERE post_status = 'publish'");
if ($query_result) {
    foreach ($query_result as $result) {
        setup_postdata($result);
        get_template_part( 'content', get_post_format() );
    }
} else {
    echo "<p>Not found</p>" ;
}
?>

See wpdb and setup_postdata.