Laravel 4.2 n+1 without eager loading - php

Question

I have a table with products
products
------------------------------------------------
id product_code purchase_type quantity
1 106 new 1
2 107 renew 3
and a pricelist for products
price_list
----------------------------------------------------------------------
id product_code purchase_type minimum maximum unit_price
1 106 new 1 25 20
2 106 new 26 50 16
3 106 new 51 100 14
When I display the products on a page, I need to display the price with the formula
getPrice(product_code, purchase_type, quantity) for every product
Using
foreach(Product::all() as $product){
{{ $product->product_code }}
{{ $product->purchase_type }}
{{ $product->quantity }}
{{ PriceList::getPrice($product->product_code, $product->purchase_type, $product->quantity) }} - this one is the n+1 problem
}
PriceList::getPrice() is something like:
public static function getPrice($productCode, $purchaseType, $quantity){
return PriceList::where('product_code', $productCode)
->where('purchase_type', $purchaseType)
->where('minimum', '>=', $quantity)
->where('maximum', '<=', $quantity)
->get()->first()->unit_price;
}
I can't seem to find a more efficient way.
And when I display over 1000 products, then it gets really slow.
I can't seem to find a way to use eager loading.

Answer 1

It is not a good idea to call model from inside loop to get data.
Instead of doing that, follow below way.
You should define relationship between Product and PriceList tables.
In Model Product.php
public function price_list(){
return $this->hasMany('PriceList','product_code');
}
In Model PriceList.php
public function product(){
return $this->belongsTo('Product','product_code');
}
In Controller File
$products = Product::with('price_list')->get();
return View::make('your_view')->with('products', $products);
In View File (file must have extention .blade.php to use below syntax)
#foreach($products as $product)
{{ $product }}
#endforeach
Note:- Print $products in controller to check results.

Answer 2

I found a way with mysql,
SELECT
`products`.`id` AS `product_id`,
`products`.`product_code` AS `product_product_code`,
`products`.`purchase_type` AS `product_purchase_type`,
`products`.`quantity` AS `product_quantity`,
`price_list`.`product_code` AS `price_list_product_code`,
`price_list`.`purchase_type` AS `price_list_purchase_type`,
`price_list`.`minimum` AS `price_list_minimum`,
`price_list`.`maximum` AS `price_list_maximum`,
`price_list`.`unit_price` AS `price_list_unit_price`
FROM
`products`
LEFT JOIN `price_list` ON `products`.`product_code` = `price_list`.`product_code`
AND `products`.`purchase_type` = price_list.purchase_type
AND `products`.`quantity` >= price_list.minimum
AND `products`.`quantity` <= price_list.maximum
ORDER BY
`products`.`id` ASC
http://sqlfiddle.com/#!9/5d6ac/2