问题
I have two tables products
and product_categories
that are associated through a third table, products_categories_products
, according to CakePHP BelongsToMany conventions (Edit: these associations are established in ProductsTable.php
and ProductCategoriesTable.php
). I want to generate a list of product categories, using the image from the best selling products to represent each category.
I can achieve my desired outcome using the following function:
public function findImages(Query $query, array $options) {
$query->select([
'ProductCategories.id',
'ProductCategories.name',
'ProductCategories__image' => '(SELECT Products.image
FROM product_categories_products AS ProductCategoriesProducts
LEFT JOIN products AS Products
ON ProductCategoriesProducts.product_id = Products.id
WHERE ProductCategoriesProducts.product_category_id = ProductCategories.id
ORDER BY Products.turnover DESC
LIMIT 1)'
])->where([
'ProductCategories.name <>' => 'Unsorted'
])->order([
'ProductCategories.name' => 'asc'
]);
return $query;
}
Is this acceptable or is there a Cake-ier way to achieve my goal? I couldn't really find anything on the topic of crafting subqueries in CakePHP 3. I just stumbled into the above solution after a couple hours of frustration. Any advice appreciated!
回答1:
Thanks to the link from user ndm_yesterday, I generated the following solution:
public function findImages(Query $query, array $options) {
$this->hasMany('ProductCategoriesProducts');
$subquery = $this->ProductCategoriesProducts->find('all')->select([
'Products.image'
])->join([
[
'table' => 'products',
'alias' => 'Products',
'type' => 'LEFT',
'conditions'=> [
'ProductCategoriesProducts.product_id = Products.id'
]
]
])->where([
'ProductCategoriesProducts.product_category_id = ProductCategories.id'
])->order([
'Products.turnover' => 'DESC'
])->limit(1);
$query->select([
'ProductCategories.id',
'ProductCategories.name',
'ProductCategories__image' => $subquery
])->where([
'ProductCategories.name <>' => 'Unsorted'
])->order([
'ProductCategories.name' => 'asc'
]);
return $query;
}
来源:https://stackoverflow.com/questions/33884603/subqueries-in-cakephp-3