merging duplicates from array of objects except for one value… php/mysql

Question

Here is a simplified version of my data. This is the result of a query using a JOIN and produces data like this:

id     name         picture
1      Foo          picture_001.jpg
1      Foo          picture_002.jpg
2      Bar          another_image.jpg
3      Baz          some_picture_001.jpg
3      Baz          some_picture_002.jpg

The output is an array of objects, which looks like this (minimised to just show ID 1's data):

print_r($my_data); // produces:

Array
(
    [0] => stdClass Object
    (
        [id] => 1
        [name] => Foo
        [picture] = picture_001.jpg
    )

    [1] => stdClass Object
    (
        [id] => 1
        [name] => Foo
        [picture] = picture_002.jpg
    )
)

This array might contain several more objects, with different ID's, names and pictures.

I am trying to cycle through each object and output the data. This I am doing like so:

foreach($object as $item)
{
    echo $item->id;
}

This does work, but as expected, produces duplicated data as a result of the join.

I have searched for a solution but I can not get my head around how to prevent this duplication from occuring.

In my data dump above, I would want the output to be:

ID 1
Name: Foo
Pictures in Foo:
  picture_001.jpg
  picture_002.jpg

ID 2
Name:Bar
Pictures in Bar
  another_image.jpg

So if an item has multiple pictures, it is grouped together.

I can provide SQL, and possibly change how the data is output, but I would like to see the methodology behind this first, and how to go about this.

Thanks in advance.

Answer 1

GROUP_CONCAT should be your solution:

SELECT id, name, 
       GROUP_CONCAT( picture ORDER BY picture SEPARATOR '<br/'> ) as pictures
FROM your_table
GROUP BY id, name

it would require some playing with it to get your formating, however it could be the way

Answer 2

$my_parsed_data = array();
foreach($mydata as $data){
  $my_parsed_data[$data->id]["id"] = $data->id;
  $my_parsed_data[$data->id]["name"] = $data->name;
  $my_parsed_data[$data->id]["photos"][] = $data->picture;
}

this solution will give you a simple array of the info the format you want... if you want an array of objects instead then you'll have to create a class that emulates this code, something like:

class ArrayList{
   private elements = array();

   public function addElement(){
      //some magic here =)
   }

}