title: Limit subquery without limiting entire query
body: <p>I am trying to implement a top-result search for a playlist. The tables are like so:<br/>
  <br/>
  Playlist: id, title<br/>
  Assignments: id, youtube_id, position<br/>
  Videos: youtube_id, title<br/>
  <br/>
  So joining them is simply: Playlist =(id)= Assignments =(youtube_id)= Videos<br/>
  <br/>
  I want to find the first playlist on a title match (Titles are not unique) and match it to each of it's videos, to bring back a list of videos in that playlist. I tried the following query:</p>
  
  <pre><code>SELECT * 
  FROM ( 
  SELECT id, title, position, youtube_id
  FROM playlists p 
  JOIN playlist_assignments pa 
  USING(id) 
  WHERE 1 and title = 'My Top Videos'
  LIMIT 1
  )d 
  JOIN videos v 
  USING (youtube_id)
  ORDER BY position ASC
  </code></pre>
  
  <p>Unfortunately, the query will only return 1 row, the playlist matched with just the first video. How can I limit the subquery to just the top result, but still have a final result of a multiple row answer?</p>