php merge arrays of the same array

Question

I have this array in php :

array:5 [
  0 => array:3 [
    "tab" => "9"
    "layout_id" => "11"
    "banners_ids" => "7"
  ]
  1 => array:3 [
    "tab" => "9"
    "layout_id" => "11"
    "banners_ids" => "8"
  ]
  2 => array:3 [
    "tab" => "10"
    "layout_id" => null
    "banners_ids" => null
  ]
  3 => array:3 [
    "tab" => "11"
    "layout_id" => null
    "banners_ids" => null
  ]
  4 => array:3 [
    "tab" => "12"
    "layout_id" => null
    "banners_ids" => null
  ]
]

And i need to merge in the same array those that have the same "tab" key to have something like this:

array:5 [
  0 => array:3 [
    "tab" => "9"
    "layout_id" => "11"
    "banners_ids" => "8,7"
  ]
  1 => array:3 [
    "tab" => "10"
    "layout_id" => null
    "banners_ids" => null
  ]
  2 => array:3 [
    "tab" => "11"
    "layout_id" => null
    "banners_ids" => null
  ]
  3 => array:3 [
    "tab" => "12"
    "layout_id" => null
    "banners_ids" => null
  ]
]

How can I reach this? I trie with a foreach and positions like current() or prev() but with no result.

Answer 1

Got distracted with things. Either use Bhaskar's answer or mine... Or combine them.

<?php

$array=json_decode('[{"tab":"9","layout_id":"11","banners_ids":"7"},{"tab":"9","layout_id":"11","banners_ids":"8"},{"tab":"10","layout_id":null,"banners_ids":null},{"tab":"11","layout_id":null,"banners_ids":null},{"tab":"12","layout_id":null,"banners_ids":null}]',true);


//var_dump($array);
$new_array=array();
foreach($array as $entry)
{
$new_array[$entry['tab']]['tab']=$entry['tab'];
$new_array[$entry['tab']]['layout_id']=$entry['layout_id'];
$new_array[$entry['tab']]['banners_ids'][]=$entry['banners_ids'];
}

foreach($new_array as $key=>$val)
{
$new_array[$key]['banners_ids']=implode(',',$new_array[$key]['banners_ids']);
}

var_dump($new_array);