Group results after join? - php

Question

So, I have three tables. Movies, movies_genres and genres. I want to get a movie by its Id, and also join its genres in the result. I managed to join the results, but it doesn't display as i want it to. I'm not sure if what I'm asking is possible.
This is my query:
SELECT `movies`.*, GROUP_CONCAT(genres.id) AS genre_id, GROUP_CONCAT(genres.name) AS genre_name
FROM (`movies`)
INNER JOIN `movies_genres`
ON `movies_genres`.`movie_id` = `movies`.`id`
INNER JOIN `genres`
ON `genres`.`id` = `movies_genres`.`genre_id` WHERE `movies`.`id` = 19908
GROUP BY `movies`.`id`
The query was generated by Codeigniters Active Record class, here is the Codeigniter code if that helps:
$this->db->select('movies.*, GROUP_CONCAT(genres.id) AS genre_id, GROUP_CONCAT(genres.name) AS genre_name');
$this->db->from('movies');
$this->db->where('movies.id', $movie_id);
$this->db->join('movies_genres', 'movies_genres.movie_id = movies.id', 'inner');
$this->db->join('genres', 'genres.id = movies_genres.genre_id', 'inner');
$this->db->group_by('movies.id');
Here is the result i'm currently getting:
Array
(
[id] => 19908
[movie_title] => Zombieland
[overview] => An easily spooked guy...
[genre_id] => 28,12,35,27
[genre_name] => Action,Adventure,Comedy,Horror
)
And this is what I want:
Array
(
[id] => 19908
[movie_title] => Zombieland
[overview] => An easily spooked guy...
[genres] => array(
0 => array(
'id' => 28,
'name' => Action
),
1 => array(
'id' => 12,
'name' => Adventure
),
1 => array(
'id' => 35,
'name' => Comedy
),
1 => array(
'id' => 27,
'name' => Horror
)
)
)
Is this possible, and if so, how?

Answer 1

The query you listed will have n rows (where n = # of movies) whereas the query it seems you want will have many more rows (# of movie_genre's entries). You're probably better off leaving that query as it is, and doing some post processing.
Consider:
After you get it, just run your result (e.g. $result) array through something like:
foreach($result as &$row)
{
// Split over commas
$gi_elements = explode(',', $row['genre_id']);
$gn_elements = explode(',', $row['genre_name']);
// Build genre
$row['genre'] = array();
for($i=0; $i<count($gi_elements); $i++)
{
$row['genre'][] = array('id' => $gi_elements[$i], 'name' => $gn_elements[$i]);
}
// Cleanup
unset($row['genre_id']);
unset($row['genre_name']);
}
Afterwards, $results will look exactly as you wish without extra database work.
EDIT: Fixed some typos.