Eloquent With Min with min of related models

TL;DR In Laravel, Eloquent's min method can be used with related models to retrieve products with the lowest price in each category by combining the power of with and pluck.

Mastering Eloquent: Retrieving Related Models with Min

As a Laravel developer, you're likely no stranger to Eloquent, the powerful ORM (Object-Relational Mapping) system that makes interacting with your database a breeze. But have you ever needed to retrieve related models with the minimum value? Perhaps you're building an e-commerce platform and want to fetch products with the lowest price in each category. In this article, we'll delve into how to use Eloquent's min method with related models to achieve just that.

Retrieving Related Models with Min: A Simple Example

Let's consider a simple example where we have two models: Product and Category. Each product belongs to one category, and we want to fetch the product with the lowest price in each category.

// Define the relationships
class Product extends Model
{
    public function category()
    {
        return $this->belongsTo(Category::class);
    }
}

class Category extends Model
{
    public function products()
    {
        return $this->hasMany(Product::class);
    }
}

Now, let's write a query to fetch the product with the lowest price in each category:

$products = Product::selectRaw('category_id, min(price) as min_price')
                ->join('categories', 'products.category_id', '=', 'categories.id')
                ->groupBy('category_id')
                ->get();

This will return a collection of products with the minimum price in each category. However, we're not quite there yet! We want to fetch the actual product instances, not just their IDs and prices.

The Power of with

Here's where Eloquent's with method comes to our rescue:

$products = Product::selectRaw('category_id')
                ->join('categories', 'products.category_id', '=', 'categories.id')
                ->groupBy('category_id')
                ->min('price')
                ->with(['category'])
                ->get();

By calling with after the min method, we're telling Eloquent to fetch the related category instances for each product. However, this will return a collection of arrays, not model instances.

The Final Touch

To get the final result, we need to use Eloquent's pluck method:

$products = Product::selectRaw('category_id')
                ->join('categories', 'products.category_id', '=', 'categories.id')
                ->groupBy('category_id')
                ->min('price')
                ->with(['category'])
                ->get()
                ->pluck('product');

This will return a collection of product instances with the minimum price in each category.

Conclusion

In this article, we've seen how to use Eloquent's min method with related models to fetch products with the lowest price in each category. By combining the power of with and pluck, we can retrieve the desired data with minimal effort. Whether you're building a complex e-commerce platform or just want to master the intricacies of Laravel, understanding this technique will serve you well.

Example Use Cases

• Fetching products with the minimum price in each category
• Retrieving users with the lowest balance in each group
• Finding orders with the highest total value for each customer

By applying this knowledge to your own projects, you'll be able to write more efficient and effective queries that save time and reduce complexity. Happy coding!