Question

I have a SQL statement which is collating lots of info from several tables in my Android application, using SQLite3. Currently I have to insert the master id in several places, and I’d like to know if there’s a way to reduce this so that I only have to put the id in once (note – the id is being inserted where the question marks currently are – so can I reduce this so that I only have one question mark?):

SELECT m.movie_id, m.title, m.synopsis, m.review, m.certificate, m.duration, m.release_year, actors, directors, genres, video_url, video_title, video_thumbnail_url
FROM movies m
INNER JOIN 
(
  SELECT v.video_url as video_url, v.title as video_title, v.thumbnail_url as video_thumbnail_url, m.movie_id 
  FROM movies m
  LEFT JOIN videos v 
  ON m.movie_id = v.movie_id
  WHERE m.movie_id = ?
  ORDER BY v.insert_order 
  LIMIT 1
) trailer_group
ON trailer_group.movie_id = m.movie_id, 
(
  SELECT movie_id, group_concat(name, ', ') actors 
  FROM
    (
      SELECT m.movie_id, a.name
      FROM movies m
      LEFT JOIN movie_actors a
      ON m.movie_id = a.movie_id
      WHERE m.movie_id = ?
      ORDER BY m.movie_id, a.insert_order
    ) 
) actor_group
ON actor_group.movie_id = m.movie_id, 
(
  SELECT movie_id, group_concat(name, ', ') directors 
  FROM
    (
      SELECT m.movie_id, d.name
      FROM movies m
      LEFT JOIN movie_directors d
      ON m.movie_id = d.movie_id
      WHERE m.movie_id = ?
      ORDER BY m.movie_id, d.insert_order
    ) 
) director_group 
ON director_group.movie_id = m.movie_id, 
(
  SELECT movie_id, group_concat(name, ', ') genres 
  FROM
    (
      SELECT m.movie_id, g.name
      FROM movies m
      LEFT JOIN movie_genres g
      ON m.movie_id = g.movie_id
      WHERE m.movie_id = ?
      ORDER BY m.movie_id, g.insert_order
    ) 
) genre_group 
ON genre_group.movie_id = m.movie_id

Answer 1

SQLLite syntax seems a bit off from what I’m used to, but you should be able to only list the predicate once:

SELECT * from movies m
LEFT JOIN videos v ON v.movie_id = m.movie_id
LEFT JOIN actors a ON a.movie_id = m.movie_id
...
WHERE m.movie_id = ?

Unless there’s something I’m missing, there should be no reason to list it multiple times.