Though I don't know your database architecture, I have the feeling it isn't optimal.
That said, IF the fields you want from both the featured posts and posts tables are for the most part identical, maybe a UNION would work. For example, if you wanted one featured post and then ten "regular" posts, a query something like this could work
(SELECT somefield FROM featured_posts_table ORDER BY somefield LIMIT 1)
(SELECT somefield FROM posts_table ORDER BY somefield LIMIT 10);