Reducing and combining array - php

Question

I am trying to create an array that succinctly gives me the following:
ID of a component part
ID of the supplier for that component part
The volume breakpoints, and their associated unit costs
I am using Laravel 5.2, although this is a more general PHP question.
So, I have a database table that looks like this:
I have a function, as below, to get some prices of components:
public function get_component_prices()
{
$components = DB::table('component_supplier')
->select('component_id', 'supplier_id', 'volume', 'unit_cost')
->get();
$prices = [];
foreach ($components as $component) {
array_push($prices, ["component_id" => $component->component_id, "supplier_id" => $component->supplier_id, "volumes" => [$component->volume => $component->unit_cost]]);
}
dd($prices);
}
This gives me the array:
array:7 [▼
0 => array:3 [▼
"component_id" => 3
"supplier_id" => 1
"volumes" => array:1 [▼
100 => "1.5000"
]
]
1 => array:3 [▼
"component_id" => 3
"supplier_id" => 1
"volumes" => array:1 [▼
207 => "1.0100"
]
]
2 => array:3 [▼
"component_id" => 3
"supplier_id" => 1
"volumes" => array:1 [▼
500 => "0.8000"
]
]
3 => array:3 [▼
"component_id" => 3
"supplier_id" => 1
"volumes" => array:1 [▼
1000 => "0.4000"
]
]
4 => array:3 [▼
"component_id" => 3
"supplier_id" => 2
"volumes" => array:1 [▼
10000 => "0.2000"
]
]
5 => array:3 [▼
"component_id" => 4
"supplier_id" => 2
"volumes" => array:1 [▼
100 => "0.1000"
]
]
6 => array:3 [▼
"component_id" => 4
"supplier_id" => 2
"volumes" => array:1 [▼
500 => "0.0700"
]
]
]
You can see that certain suppliers and components have multiple volumes.
Therefore, I'd like to try to group the array a bit better, combining the repeated parts - perhaps like so, for example:
6 => array:3 [▼
"component_id" => 4
"supplier_id" => 2
"volumes" => array:3 [▼
100 => "0.1000",
500 => "0.0700"
]
]
So that for each component_id and supplier_id group, there's a set of 'volumes'.
Any advice is much appreciated... I have been trying for hours to get the array sorted!

Answer 1

In Mysql, you can do something like this
SELECT component_id, supplier_id,
GROUP_CONCAT(volume, ':', unit_cost) AS volumes
FROM component_supplier
GROUP BY CONCAT(component_id, supplier_id)
http://sqlfiddle.com/#!9/cb7bb/1
Then you can simply loop this query in PHP and explode volumes field by the comma.