Question

I’m creating an API for my mobile application. I’m developing this with PHP MYSQL and the Slim framework (which is largely irrelevant for this problem).

I’m trying to pull multiple “venues” from my mysql database, and retrieve multiple “venue_images” for each “venue”. The database:

venues        venue_images
------        ------------
id PK         image_venue_id FK (to venues)
venue_name    image_path
active

I then need to output the data in this format:

{
  "completed_in":0.01068,
  "returned":10,
  "results":[
    {
      "venue_id":"1",
      "venue_name":"NameHere",
      "images": [
         {
           "image_path":"http://www.pathhere.com"
         },
         {
           "image_path":"http://www.pathhere2.com"
         }
      ]
    }
  ]
}

So basically, the images are iterated multiple times for each venue.

My current code is:

$sql = "
    SELECT
         venues.id, venues.venue_name, venues.active,
         venue_images.image_venue_id, venue_images.image_path
    FROM
         venues
    LEFT JOIN 
         venue_images ON venue_images.image_venue_id = venues.id
    WHERE
         venues.active = 1
    LIMIT 0, 10
    ";

    $data = ORM::for_table('venues')->raw_query($sql, array())->find_many();
         if($data) {
        foreach ($data as $post) {
            $results[] = array (
                 'venue_id' => $post->id,
                 'venue_name' => $post->venue_name,
                 'images' => $post->image_path
            );
        }

        //Build full json
        $time = round((microTimer() - START_TIME), 5);
        $result = array(
             'completed_in' => $time,
             'returned' => count($results),
             'results' => $results
        );
        //Print JSON
        echo indent(stripslashes(json_encode($result)));
    } else {
         echo "Nothing found";
    }

My current code works, however it produces this:

{
  "completed_in":0.01068,
  "returned":10,
  "results":[
    {
      "venue_id":"1",
      "venue_name":"The Bunker",
      "images":"https://s3.amazonaws.com/barholla/venues/1352383950-qPXNShGR6ikoafj_n.jpg"
    },
    {
      "venue_id":"1",
      "venue_name":"The Bunker",
      "images":"https://s3.amazonaws.com/barholla/venues/1352384236-RUfkGAWsCfAVdPm_n.jpg"
    }
]
}

There’s two images for “The Bunker”. Instead of storing the images within the venue array, it’s creating a duplicate row of “The Bunker”, with the second image. Like I said earlier, I need to have multiple images iterating within each venue. Any help would be much appreciated! Thanks!

Answer 1

You want to use GROUP_CONCAT

Something like this (not 100% accurate probably 🙂 )

$sql = "
    SELECT
         v.id, v.venue_name, v.active,
         GROUP_CONCAT(i.image_path) as venue_image_string
    FROM
         venues v
    LEFT JOIN 
         venue_images i ON i.image_venue_id = v.id
    WHERE
         v.active = 1
    GROUP BY i.image_venue_id
    LIMIT 0, 10
";

You may have to fiddle a little but should put you on the right track (note: provides venue_image_string as CSV)