category_model.php

<?php

public function find_all_by_country($country)
{
	return $this
		->select('DISTINCT categories.*')
		->join('categories_products', 'categories_products.category_id', 'categories.id')
		->join('products', 'products.id', 'categories_products.product_id')
		->join('product_skus', 'product_skus.product_id', 'products.id')
		->join('countries_product_skus', 'countries_product_skus.product_sku_id', 'product_skus.id')
		->where('countries_product_skus.country_id', $country->id)
		->where('categories.category_parent_id', NULL)
		->find_all();
}