Laravel: How to count data in database? - php

Question

I want to make a list of students to know how many products each student buys. I have two tables : Member and Orders. In Orders table have column member_id and product_id. I want to count how many products each student buys. I can get list of student but i can't count how many products each student buys.
public function index()
{
$students = Member::getStudents();
$order = Order::where('member_id', $students->id)->count();
return view('admin.student.index', compact('students'));
}
But it appears an error:
Property [id] does not exist on this collection instance.
function getStudents()
public static function getStudents()
{
$members = Member::where('member_type_id', BaseModel::$student)->get();
for ($idxMember = 0; $idxMember < count($members); $idxMember++) {
if ( $members[$idxMember]->user_id ) {
$members[$idxMember]->username = User::find($members[$idxMember]->user_id)->username;
}
}
return $members;
}

Answer 1

I think it is because you get a collection on id.
so you should foreach your collection and get specific ids.
public function index() {
$students = Member::getStudents();
foreach($students as $student ) {
$order = Order::where('member_id', $student->id)->count();
}
return view('admin.student.index', compact('students'));
}

Answer 2

I suggest to use relationships in Database. It would be more easy and simple.
In orders table, there is a column called member_id which reference to id column in members table. (Keep attention to singular plural usage)
Refer Laravel Documentation for foreign key design and implementation.
You need 2 models, Member and Order. You should define the relationship as below.
Since this is One To Many Relationship,
In Member Model,
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Member extends Model
{
/**
* Get the orders for the member.
*/
public function orders()
{
return $this->hasMany('App\Order');
}
}
?>
In Order Model,
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Order extends Model
{
/**
* Get the member that owns the order.
*/
public function member()
{
return $this->belongsTo('App\Member');
}
}
?>
Now you can get order count per user using this code.
Member::find(MEMBER_ID)->orders->count();
This will return order count of the selected member.
Please refer the Laravel Documentation here.
Relationships | One To Many | One To Many (Inverse)

Answer 3

You can achieve this by simply using laravel relationship
In order to do this please follow below steps
First, create two relation in members model
public function orders()
{
return $this->hasMany('App\Models\Order', 'member_id', 'id);
}
Then retrieve the students details with orders
public function getStudents()
{
return Member::where('member_type_id', BaseModel::$student)->withCount('orders)->get();
}
Hope this helps
Thank you.

Answer 4

Sharing solution with explanation.
Objects are
Member (Student is also a member. But the Type is different)
Order (One order can have multiple products)
Product (Product will allocate with Orders and Members can place Orders)
Now If you are using Laravel. So the best way is to use Eloquent Relationships.
Model Member :
1 Define Query Scope
public function scopeStudents($query)
{
return $query->where('member_type_id', 1);
}
2 Define One to Many relation between Order and Member (One Student can have multiple orders. And I hope that other members can also have orders. So i am going to relate direct Member to Order)
public function orders()
{
return $this->hasMany('App\Order');
}
and
public function products()
{
return $this->hasManyThrough('App\Product', 'App\Order');
}
Model Order :
1 Define relation with Member Model for One to Many
public function member()
{
return $this->belongsTo('App\Member');
}
2 Define one to many between Order and Product
public function products()
{
return $this->hasMany('App\Product');
}
Model Product :
1 Define Order Product Relation
public function order()
{
return $this->belongsTo('App\Order');
}
Now the Model work is done. Only data fetching is remaining. Tell me in comments if you think below code is less and useful and easy to understand.
Controller Member :
1 Index Function :
// this will fetch all students with their orders and products
$data = Member::students()->with('orders', 'products')->get();
// this will fetch all students with their orders and order's products
$data = Member::students()->with('orders.products')->get();
// this will fetch all students with their orders count and products count
$data = Member::students()->withCount('orders', 'products')->get();